added lint changes, started migrating

packages/stream_chat_flutter/test/src/attachment_actions_modal_test.dart

@@ -239,7 +239,7 @@ void main() {
         ),
       );
       await tester.tap(find.text('Show in Chat'));
-      verify(() => onShowMessage.call()).called(1);
+      verify(onShowMessage.call).called(1);
     },
   );
 

packages/stream_chat_flutter/test/src/attachment_widgets_test.dart

@@ -26,8 +26,8 @@ void main() {
               child: Container(
                 child: FileAttachment(
                   size: Size(
-                    300.0,
-                    300.0,
+                    300,
+                    300,
                   ),
                   message: Message(),
                   attachment: Attachment(

packages/stream_chat_flutter/test/src/channel_header_test.dart

@@ -318,7 +318,6 @@ void main() {
               body: ChannelHeader(
                 showTypingIndicator: false,
                 showBackButton: false,
-                showConnectionStateTile: false,
               ),
             ),
           ),

packages/stream_chat_flutter/test/src/reaction_bubble_test.dart

@@ -224,7 +224,6 @@ void main() {
               borderColor: Colors.red,
               backgroundColor: Colors.blue,
               maskColor: Colors.green,
-              highlightOwnReactions: true,
               reverse: true,
               flipTail: true,
               tailCirclesSpacing: 4,