chore: update message_theme.dart

Includes Diagnosticable, more descriptive field names, lerp, ==, and hashCode

packages/stream_chat_flutter/lib/src/quoted_message_widget.dart

@@ -74,7 +74,7 @@ class QuotedMessageWidget extends StatelessWidget {
   final Message message;
 
   /// The message theme
-  final MessageTheme messageTheme;
+  final MessageThemeData messageTheme;
 
   /// If true the widget will be mirrored
   final bool reverse;
@@ -139,11 +139,11 @@ class QuotedMessageWidget extends StatelessWidget {
             message: msg,
             messageTheme: isOnlyEmoji && _containsText
                 ? messageTheme.copyWith(
-                    messageText: messageTheme.messageText?.copyWith(
+                    messageTextStyle: messageTheme.messageTextStyle?.copyWith(
                     fontSize: 32,
                   ))
                 : messageTheme.copyWith(
-                    messageText: messageTheme.messageText?.copyWith(
+                    messageTextStyle: messageTheme.messageTextStyle?.copyWith(
                     fontSize: 12,
                   )),
           ),