Consider re-implementing local inspection on Dart files to run pub (FlutterDependencyInspection)

[jwren]

The LocalInspectionTools in the Flutter and Dart IntelliJ plugins have been causing more headache and possible performance issues than they have been worth, see https://github.com/flutter/flutter-intellij/issues/7623 for some context.

This feature was the ability to see pub get, and other pub actions, at the top of your Dart file if pub needed to be run. The functionality was split across the two IntelliJ plugins. After the implementation of the Dart Workspaces feature, validation of a successful pub get is more complicated than it was when this original LocalInspectionTools were implemented. In the IDEA framework LocalInspectionTools are run frequently and precaution around not searching up directory structures (read: trying to avoid possible performance issues), easily leads to annoying false positives-- a notification at the top every dart file that can't be dismissed.

Note: the functionality for having the pub actions at the top of the pubspec.yaml is still preserved with FlutterPubspecNotificationProvider and DartEditorNotificationsProvider (EditorNotificationProviders).

This issue is open as a place holder to incase the feature is missed. If we do re-implement it, consider:

• 1 implementation, not 2, both for debugging issues as well as not introducing lag in the plugin
• and, having the functionality be disabled by default.