Add `BackdropBlurContainer` #6560

Job	Run time
Build only (iOS)	3m 13s
Code Quality	5m 20s
Test (Windows, windows-latest, Debug, SingleThread)	9m 7s
Build only (Android)	7m 31s
Test (Windows, windows-latest, Debug, MultiThreaded)	9m 9s
Test (macOS, macos-latest, Debug, SingleThread)	7m 23s
Test (macOS, macos-latest, Debug, MultiThreaded)	14m 23s
Test (Linux, ubuntu-latest, Debug, SingleThread)	5m 1s
Test (Linux, ubuntu-latest, Debug, MultiThreaded)	5m 35s
Test (Linux, ubuntu-latest, Release, SingleThread)	4m 1s
Test (Linux, ubuntu-latest, Release, MultiThreaded)	5m 18s
	1h 16m 1s

Provide feedback