Update Flutter.gitignore

Remove Visual Studio Code Setting related line

Co-authored-by: Tim Hunter <thorrsson@github.com>

Flutter.gitignore

@@ -119,5 +119,4 @@ app.*.symbols
 !**/ios/**/default.pbxuser
 !**/ios/**/default.perspectivev3
 !/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
-!/dev/ci/**/Gemfile.lock
-!.vscode/settings.json
+!/dev/ci/**/Gemfile.lock