use varuint for writing/reading objectid, total properties and property key in animation reset

objectId, propertykey are definitely written as varuint, not sure if properties total needs to be, but doesn't hurt to have it that way either I think.

I'm not sure if this is everything that needs to be updated. I tried to use `generate_core_runtime` to update the flutter runtime but that made a bunch of changes like unused imports all over the place...

Diffs=
07cbce551 use varuint for writing/reading objectid, total properties and property key in animation reset (#7510)

Co-authored-by: Arthur Vivian <[email protected]>
Co-authored-by: Hernan Torrisi <[email protected]>

Author: 3 people

.rive_head

@@ -1 +1 @@
-f9b1e8ec2ff7960990f87ef855c669f6a4a86b1d
+07cbce5511e451396513f9d092a72193d41844f5

lib/src/rive_core/animation/animation_reset_factory.dart

@@ -33,15 +33,15 @@ class AnimationReset {
   }
 
   void writeObjectId(int id) {
-    _writer.writeInt8(id);
+    _writer.writeVarUint(id);
   }
 
   void writeTotalProperties(int totalProperties) {
-    _writer.writeInt8(totalProperties);
+    _writer.writeVarUint(totalProperties);
   }
 
   void writePropertyKey(int propertyKey) {
-    _writer.writeInt8(propertyKey);
+    _writer.writeVarUint(propertyKey);
   }
 
   void writeColor(int value) {
@@ -74,15 +74,15 @@ class AnimationReset {
     reader.readIndex = 0;
     while (reader.readIndex < _dataSize) {
       // First we read the object's id
-      final objectIntId = reader.readInt8();
+      final objectIntId = reader.readVarUint();
       final objectId = resolveId(objectIntId);
       final object = core.resolve<Core>(objectId);
       // Second we read how many keyframed properties it has
-      final totalProperties = reader.readInt8();
+      final totalProperties = reader.readVarUint();
       int currentPropertyIndex = 0;
       while (currentPropertyIndex < totalProperties) {
         // Third we read the property key for each property
-        final propertyKey = reader.readInt8();
+        final propertyKey = reader.readVarUint();
         // Fourth we read the property value for each property
         if (_isDouble(propertyKey, object!)) {
           double value = reader.readFloat32();