Android: link AbortController polyfill into BabylonNativeJNI

AppContext.cpp includes <Babylon/Polyfills/AbortController.h> and calls
Babylon::Polyfills::AbortController::Initialize(env), but the Android-
specific CMakeLists at Apps/Playground/Android/BabylonNative did not
add AbortController to BabylonNativeJNI's PRIVATE link libraries. The
header is published only by the AbortController target, so Android CI
failed with 'fatal error: Babylon/Polyfills/AbortController.h file not
found'. Linux/macOS/Windows builds were fine because they use the main
Apps/Playground/CMakeLists.txt which already links AbortController.

Mirror the change there so Android picks up the include directory.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: bkaradzic-microsoft

Apps/Playground/Android/BabylonNative/CMakeLists.txt

@@ -25,6 +25,7 @@ target_link_libraries(BabylonNativeJNI
     PRIVATE EGL
     PRIVATE log
     PRIVATE -lz
+    PRIVATE AbortController
     PRIVATE AndroidExtensions
     PRIVATE AppRuntime
     PRIVATE Blob