add docs on android limitation for screen orientations (#165021)

Resolves https://github.com/flutter/flutter/issues/99149

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

packages/flutter/lib/src/services/system_chrome.dart

@@ -411,6 +411,20 @@ abstract final class SystemChrome {
   ///
   /// ### Android
   ///
+  /// Android limits the [orientations](https://developer.android.com/reference/android/R.attr#screenOrientation)
+  /// to the following combinations:
+  ///
+  ///   - None (empty) - Corresponds to unspecified
+  ///   - portraitUp - Corresponds to portrait
+  ///   - landscapeLeft - Corresponds to landscape
+  ///   - portraitDown - Corresponds to reversePortrait
+  ///   - portraitUp, portraitDown - Corresponds to userPortrait
+  ///   - landscapeRight - Corresponds to reverseLandscape
+  ///   - landscapeLeft, landscapeRight - Corresponds to userLandscape
+  ///   - portraitUp, landscapeLeft, landscapeRight - Corresponds to user
+  ///   - portraitUp, portraitDown, landscapeLeft, landscapeRight - Corresponds
+  ///   to fullUser
+  ///
   /// Android screens may choose to [letterbox](https://developer.android.com/guide/practices/enhanced-letterboxing)
   /// applications that lock orientation, particularly on larger screens. When
   /// letterboxing occurs on Android, the [MediaQueryData.size] reports the