'Format code on save' option behaves globally instead of per project

## Steps to Reproduce

1. Open a project in Android Studio. Note the 'Format code on save' option.
2. Open another project.
3. Switch the option on the first project.
4. Notice the option also changed for the second project.

The UI indicates that settings are on a per-project basis.

This feature would be highly useful for Flutter contributors, who likely use dartfmt on their own projects, but can't when contributing (per Flutter style guide). I work on both and have to toggle this option every time I switch.

## Version info

```
[✓] Flutter (Channel master, v1.18.0-7.0.pre.47, on Mac OS X 10.15.4 19E287, locale en-DE)
• Flutter version 1.18.0-7.0.pre.47 at /Users/plg/development/flutter
• Framework revision 240611b05e (17 hours ago), 2020-04-23 11:54:02 -0400
• Engine revision feb94f6c97
• Dart version 2.9.0 (build 2.9.0-2.0.dev 64b8ded48b)

[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
• Android SDK at /Users/plg/Library/Android/sdk
• Platform android-stable, build-tools 29.0.3
• ANDROID_SDK_ROOT = /Users/plg/Library/Android/sdk
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b4-5784211)
• All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.3.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 11.3.1, Build version 11C505
• CocoaPods version 1.9.1

[✓] Chrome - develop for the web
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio
• Android Studio at /Applications/Android Studio with Blaze.app/Contents
• Flutter plugin version 45.1.2
• Dart plugin version 193.6494.35
• Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6222593)

[✓] Android Studio (version 3.6)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin version 45.1.1
• Dart plugin version 192.7761
• Java version OpenJDK Runtime Environment (build 1.8.0_212-release-1586-b4-5784211)

[✓] Connected device (3 available)
• macOS • macOS • darwin-x64 • Mac OS X 10.15.4 19E287
• Web Server • web-server • web-javascript • Flutter Tools
• Chrome • chrome • web-javascript • Google Chrome 81.0.4044.122

• No issues found!
```