implicit-casts:false in flutter_web_plugins (#45240)

packages/flutter_web_plugins/analysis_options.yaml

+# Override the parent analysis_options until all the repo has implicit-casts: false
+
+include: ../analysis_options.yaml
+
+analyzer:
+  strong-mode:
+    implicit-casts: false
+    implicit-dynamic: false
+
+linter:
+  rules:
+    avoid_as: false

packages/flutter_web_plugins/test/plugin_registry_test.dart

@@ -56,7 +56,7 @@ void main() {
       final List<String> loggedMessages = <String>[];
       ServicesBinding.instance.defaultBinaryMessenger
           .setMessageHandler('test_send', (ByteData data) {
-        loggedMessages.add(codec.decodeMessage(data));
+        loggedMessages.add(codec.decodeMessage(data) as String);
         return null;
       });