Fix regression in desktop decor visibility for bubble tasks.

In ag/32735920, bubble task visibility was changed to use task
reordering instead of the hidden property. As part of this, the
`alwaysOnTop` flag is reset to false when a bubble collapses, allowing
the task to be moved to the bottom of the stack.

However, desktop window decor logic uses the `alwaysOnTop` flag to
determine whether to show decor elements like the app handle. This led
to a regression where collapsed bubble tasks (which have `alwaysOnTop`
set to false) incorrectly triggered desktop decor logic.

This change fixes the issue by introducing a check in
`AppHandleAndHeaderVisibilityHelper` to recognize stable bubble tasks
via `BubbleController`, ensuring that collapsed bubble tasks are
excluded from decor rendering decisions even when `alwaysOnTop` is
false.

Bug: 388630258
Bug: 408389476
Flag: com.android.wm.shell.enable_create_any_bubble
Flag: com.android.window.flags.exclude_task_from_recents
Test: atest WMShellUnitTests:DesktopModeWindowDecorViewModelTests
Test: atest WMShellRobolectricTests:BubbleControllerTest
Test: atest WMShellMultivalentTestsOnDevice:BubbleControllerTest
Test: atest systemui-bubble-1-jank-suite \
--request-upload-result \
-- --enable-module-dynamic-download \
--module-arg systemui-bubble-1-jank-suite:strict-include-metric-filter:'perfetto_ft_systemui-missed_app_frames-mean' \
--test-arg com.android.tradefed.testtype.AndroidJUnitTest:class:android.platform.test.scenario.sysui.bubble.ShowMultipleBubblesAndSwitchMicrobenchmark
http://ab/I40600010387932237 (flag disabled, 6.24)
http://ab/I30400010385432590 (flag enabled, 10.36)
Change-Id: I0ce2060bed50ff973f1046f11a9da4c6872f5333

Change-Id: I9c20f3e534f2dc9e5d7a62da83777d2ee2eda5d6