Send full user agent header to server during OIDC authentication and when viewing Account and Device management screens (#7997)

Author: hughns

Riot/Modules/Authentication/SSO/SSOAuthentificationSession.swift

@@ -7,6 +7,7 @@
 
 import Foundation
 import AuthenticationServices
+import MatrixSDK
 
 /// Provides context to target where in an application's UI the authorization view should be shown.
 class SSOAuthenticationSessionContextProvider: NSObject, SSOAuthenticationSessionContextProviding, ASWebAuthenticationPresentationContextProviding {
@@ -62,6 +63,14 @@ final class SSOAuthentificationSession: SSOAuthentificationSessionProtocol {
             authentificationSession.presentationContextProvider = asWebContextProvider
         }
 
+        if #available(iOS 17.4, *),
+           let httpAdditionalHeaders = MXSDKOptions.sharedInstance().httpAdditionalHeaders,
+           let userAgent = httpAdditionalHeaders["User-Agent"] {
+            authentificationSession.additionalHeaderFields = [
+                "X-Element-User-Agent": userAgent
+            ]
+        }
+        
         authentificationSession.start()
     }