[AND-199] Implement ComposerActionsTheme for customizing the message composer action icons.

[VelikovPetar]

🎯 Goal

Linear: https://linear.app/stream/issue/AND-199/implement-icon-customisation-options-for-messagecomposer-in-compose
Exposes a way to customise the default message composer icons (attachments / commands / send) without overriding each component separately.

🛠 Implementation details

• Define new ComposerActionsTheme which holds an IconContainerStyle for each default action in the composer (attachments / commands / send)
• Expose the actionsTheme : ComposerActionsTheme via the MessageComposerTheme
• The composer action icons styling is now taken from ChatTheme.messageComposerTheme.actionsTheme

Example (overriding the default attachments button):

val actionsTheme = ComposerActionsTheme.defaultTheme(colors)
val messageComposerTheme = MessageComposerTheme
      .defaultTheme(isInDarkMode, typography, shapes, colors)
      .copy(
          actionsTheme = actionsTheme.copy(
              attachmentsButton = IconContainerStyle(
                  size = ComponentSize.square(48.dp),
                  padding = ComponentPadding.all(8.dp),
                  icon = IconStyle(
                     painter = painterResource(id = R.drawable.stream_compose_ic_image_picker),
                     tint = colors.textLowEmphasis,
                     size = ComponentSize.square(32.dp),
                  )
              ),
            )
        )
ChatTheme(
  // ...
  messageComposerTheme = messageComposerTheme
) { }

Will produce the following message composer (sample app):

Example

🧪 Testing

1. Apply the provided patch
2. Open the compose sample app
3. Open a channel
4. The message composer should have an updated "Attachments" icon

Provide the patch summary here

Index: stream-chat-android-compose-sample/src/main/java/io/getstream/chat/android/compose/sample/ui/MessagesActivity.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/stream-chat-android-compose-sample/src/main/java/io/getstream/chat/android/compose/sample/ui/MessagesActivity.kt b/stream-chat-android-compose-sample/src/main/java/io/getstream/chat/android/compose/sample/ui/MessagesActivity.kt
--- a/stream-chat-android-compose-sample/src/main/java/io/getstream/chat/android/compose/sample/ui/MessagesActivity.kt	(revision 803974da8bc950749488d85adfade6ccdb394d6b)
+++ b/stream-chat-android-compose-sample/src/main/java/io/getstream/chat/android/compose/sample/ui/MessagesActivity.kt	(date 1735059477925)
@@ -80,6 +80,11 @@
 import io.getstream.chat.android.compose.ui.messages.list.MessageList
 import io.getstream.chat.android.compose.ui.theme.AttachmentPickerTheme
 import io.getstream.chat.android.compose.ui.theme.ChatTheme
+import io.getstream.chat.android.compose.ui.theme.ComponentPadding
+import io.getstream.chat.android.compose.ui.theme.ComponentSize
+import io.getstream.chat.android.compose.ui.theme.ComposerActionsTheme
+import io.getstream.chat.android.compose.ui.theme.IconContainerStyle
+import io.getstream.chat.android.compose.ui.theme.IconStyle
 import io.getstream.chat.android.compose.ui.theme.MessageComposerTheme
 import io.getstream.chat.android.compose.ui.theme.MessageOptionsTheme
 import io.getstream.chat.android.compose.ui.theme.MessageTheme
@@ -151,7 +156,22 @@
         val colors = if (isInDarkMode) StreamColors.defaultDarkColors() else StreamColors.defaultColors()
         val typography = StreamTypography.defaultTypography()
         val shapes = StreamShapes.defaultShapes()
-        val messageComposerTheme = MessageComposerTheme.defaultTheme(isInDarkMode, typography, shapes, colors)
+        val actionsTheme = ComposerActionsTheme.defaultTheme(colors)
+        val messageComposerTheme = MessageComposerTheme
+            .defaultTheme(isInDarkMode, typography, shapes, colors)
+            .copy(
+                actionsTheme = actionsTheme.copy(
+                    attachmentsButton = IconContainerStyle(
+                        size = ComponentSize.square(48.dp),
+                        padding = ComponentPadding.all(8.dp),
+                        icon = IconStyle(
+                            painter = painterResource(id = R.drawable.stream_compose_ic_image_picker),
+                            tint = colors.textLowEmphasis,
+                            size = ComponentSize.square(32.dp),
+                        )
+                    ),
+                )
+            )
         val ownMessageTheme = MessageTheme.defaultOwnTheme(isInDarkMode, typography, shapes, colors)
         ChatTheme(
             isInDarkMode = isInDarkMode,
@@ -162,19 +182,7 @@
             autoTranslationEnabled = ChatApp.autoTranslationEnabled,
             isComposerLinkPreviewEnabled = ChatApp.isComposerLinkPreviewEnabled,
             allowUIAutomationTest = true,
-            messageComposerTheme = messageComposerTheme.let {
-                it.copy(
-                    attachmentCancelIcon = it.attachmentCancelIcon.copy(
-                        painter = painterResource(id = R.drawable.stream_compose_ic_clear),
-                        tint = colors.overlayDark,
-                        backgroundColor = colors.appBackground,
-                    ),
-                    audioRecording = it.audioRecording.copy(
-                        enabled = true,
-                        showRecordButtonOverSend = false,
-                    ),
-                )
-            },
+            messageComposerTheme = messageComposerTheme,
             attachmentPickerTheme = AttachmentPickerTheme.defaultTheme(colors).copy(
                 backgroundOverlay = colors.overlayDark,
                 backgroundSecondary = colors.inputBackground,