feat: support Flutter stable channel (#581)

* feat: adjust toggle list block

* chore: upgrade Flutter to master channel

* chore: upgrade pbxproj

* fix: toolbar copy button not closing on mobile editor

* fix: formatting issues and add missing commas

* chore: add stable branch to GitHub Actions workflow

* chore: add missing trailing commas

* chore: adjust indentation padding in block component
configuration and unit tests

.gitignore

@@ -129,4 +129,6 @@ app.*.symbols
 !**/ios/**/default.pbxuser
 !**/ios/**/default.perspectivev3
 !/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
-!/dev/ci/**/Gemfile.lock
+!/dev/ci/**/Gemfile.lock
+
+.fvm/