24293 [Windows] Fix crash of TextInputPlugin on empty model  (cla: yes, waiting for tree to go green)

24306 [flutter_releases] Flutter Engine 1.26.0-17.5.pre Beta Cherrypicks (cla: yes)

24308 Fix FlutterPlatformViewSemanticsContainer retain cycle with SemanticsObject (cla: yes, platform-ios, waiting for tree to go green)

24318 Windows: linker compatibility with AppContainer for winuwp target (cla: yes)

24327 [embedder] [metal] Embedder API can support externally composited Metal textures (cla: yes)

24331 Revert “Reland “[metal] Darwin unified external metal textures (#2415… (cla: yes, platform-ios, waiting for tree to go green)