Warning: CocoaPods not installed. Skipping pod install.
CocoaPods is used to retrieve the iOS and macOS platform side’s plugin code that responds to your plugin usage on the Dart side.
Without CocoaPods, plugins will not work on iOS or macOS.
For more info, see https://flutter.dev/platform-plugins
To install see https://guides.cocoapods.org/using/getting-started.html#installation for instructions.

Warning: CocoaPods not installed. Skipping pod install.
  CocoaPods is used to retrieve the iOS and macOS platform side's plugin code that responds to your plugin usage on the Dart side.
  Without CocoaPods, plugins will not work on iOS or macOS.
  For more info, see https://flutter.dev/platform-plugins
To install see https://guides.cocoapods.org/using/getting-started.html#installation for instructions.

CocoaPods not installed or not in valid state.
Error launching application on iPhone 11.

ターミナルからAndroid Studioを起動するとエラーが出ないようなので、こちらを実行

open /Applications/Android\ Studio.app

動きました!

参考記事

Android StudioでFlutterアプリ（iPhoneエミュレータ）を実行すると’Warning: CocoaPods not installed. Skipping pod install.’