[flutter_tools] Display "no platforms" message based on results when creating plugins project (#70215)

* Update floating_action_button.dart

* Fix default hover elevation

* revert letter spacing change

* add test

* Update floating_action_button.dart

* Update floating_action_button_test.dart

20caf5496 Roll Dart SDK from cd7b857e70a7 to ce76503f5b46 (1 revision) (flutter/engine#22738) (#71231)

This reverts commit 358f9b0e.

This reverts commit b18f1b81.

* 53fc019aa Split AOT Android Embedder and shell (flutter/engine#22179)

* fc5581460 Implement Scene.toImage() in CanvasKit mode. (flutter/engine#22085)

* c45e02a02 Roll Dart SDK from 12fded61a2bc to a06d469024fd (1 revision) (flutter/engine#22623)

* 550c75025 Remove opt outs for dart:ui (flutter/engine#22603)

* f2803ac01 [fuchsia] shader warmup fixes (flutter/engine#22439)

* ce94c4e3a Roll Dart SDK from a06d469024fd to b8fea79a2549 (1 revision) (flutter/engine#22630)

* 76b6acb85 Roll Fuchsia Linux SDK from aAb3NJv_h... to X1ue-JZsc... (flutter/engine#22631)

* 976e8874d Roll Skia from ed289e777cfa to 9dce4d081f8a (3 revisions) (flutter/engine#22632)

* 885bd6516 Roll Fuchsia Mac SDK from DQpWjEN59... to wGZWtwuY4... (flutter/engine#22633)

* 8971b8295 Roll Dart SDK from b8fea79a2549 to 861ebcb175b6 (1 revision) (flutter/engine#22634)

* a09cdfdbe Roll Skia from 9dce4d081f8a to 8c5889937172 (1 revision) (flutter/engine#22635)

* a9f332c04 Roll Dart SDK from 861ebcb175b6 to 1adf3d5fa9d0 (1 revision) (flutter/engine#22636)

* 1bf5c8b08 [web] Implement tilemode for gradient shaders. (flutter/engine#22597)

* 97cacfbfe Add more runtime intrinsic symbols to the export checker script (flutter/engine#22641)

Adds a new Luci test shard that runs flutter/plugins tests.

For now only the analysis phase of the flutter/plugins test suite is executed.

Manual invocation on Luci completed successfully: https://luci-milo.appspot.com/raw/build/logs.chromium.org/flutter/led/amirha_google.com/3210bb2dac01fca71b7db04dda02fa6ccd4df025afd55abea1970d26087d4962/+/annotations

This reverts commit 8e73bab9.