This adds a smoke test for every single API example. It also fixes 17 tests that had bugs in them, or were otherwise broken, and even fixes one actual bug in the framework, and one limitation in the framework.

The bug in the framework is that NetworkImage's _loadAsync method had await response.drain<List<int>>();, but if the response is null, it will throw a cryptic exception saying that Null can't be assigned to List<int>. The fix was just to use await response.drain<void>(); instead.

The limitation is that RelativePositionedTransition takes an Animation<Rect> rect parameter, and if you want to use a RectTween with it, the value emitted there is Rect?, and one of the examples was just casting from Animation<Rect> to Animation<Rect?>, which is invalid, so I modified RelativePositionedTransition to take a Rect? and just use Rect.zero if the rect is null.

520be3012 Roll Dart SDK from 1998f61b08f7 to f452a6585cbd (2 revisions) (flutter/engine#28906) (#90877)

8a71e0ee4 [camera] Fix IllegalStateException being thrown in Android implementation when switching activities. (flutter/plugins#4319) (#90857)

94e5cb8b2 Roll Dart SDK from 06093fe5921e to 1998f61b08f7 (1 revision) (flutter/engine#28899) (#90852)

80b5d2ed3 [ci] Temporary run publish task on Flutter stable channel. (flutter/plugins#4388) (#90836)

5ec61962d [in_app_purchase] Bump dependencies on json_serializable, build_runner (flutter/plugins#4386) (#90823)

1564d21ce Roll Dart SDK from 9e2228a0e880 to 0cddaa9859a5 (1 revision) (flutter/engine#28874) (#90770)

3248e8b64 Roll Dart SDK from 7e8e12d4d296 to 1a4db5ddd0ea (3 revisions) (flutter/engine#28851) (#90702)

This fixes #90044 by limiting the effect of useDeleteButtonTooltip to the delete button, instead of both the main tooltip and the delete button. This means that when useDeleteButtonTooltip was false, it used to not display the main tooltip either, but now it does.