##結論
　Android Studio　がVer４．１なら何もしなくて良い
　（Flutterのバグだったようです）

##現状

flutter plugin を Android Studio でインストールした
flutter doctor が Android Studio の flutter plugin を認識しない
Android Studio では flutter plugin を認識している

##Android StudioにFulutter Pluginのインストールは終わっている状態

##パスも通っている

which flutter
/Users/Name/Developer/flutter/bin/flutter

##以下を実行

flutter doctor -v
[✓] Flutter (Channel stable, 1.22.5, on macOS 11.1 20C69 darwin-x64, locale ja-JP)
    • Flutter version 1.22.5 at /Users/gototakahiro/Developer/flutter
    • Framework revision 7891006299 (3 weeks ago), 2020-12-10 11:54:40 -0800
    • Engine revision 2c956a31c0
    • Dart version 2.10.4

 
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
    • Android SDK at /Users/gototakahiro/Library/Android/sdk
    • Platform android-30, build-tools 30.0.2
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 12.3)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.3, Build version 12C33
    • CocoaPods version 1.10.0

[!] Android Studio (version 4.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)

[✓] VS Code (version 1.52.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.18.0

[✓] Connected device (1 available)
    • iPhone 12 Pro Max (mobile) • D3145483-24EE-4418-8C4A-BF1B236F7DC5 • ios • com.apple.CoreSimulator.SimRuntime.iOS-14-3 (simulator)

! Doctor found issues in 1 category.

##解決したいエラー

Flutter plugin not installed; this adds Flutter specific functionality.
Dart plugin not installed; this adds Dart specific functionality.

##参考
https://www.youtube.com/watch?v=17o5izTunfg