Collapse bubble on non-bubbled activity transition.

The BubblesTransitionObserver is updated to handle activity transitions
involving expanded bubbles. Previously, an activity launched from a
notification into an already expanded bubble's task would incorrectly
cause the bubble to collapse. This change leverages the task ID from
ActivityTransitionInfo (introduced in a preceding change) to determine
if the transitioning activity belongs to a bubble task in the stack. If
the target task is bubbled, the expanded bubble is preserved, thus
resolving the erroneous collapse.

This fix allows the observer to collapse the bubble when an activity
transition targets a different, non-bubbled task, such as an activity
launched from a quick settings tile into a fullscreen task. It also
collapses an expanded bubble if the underlying fullscreen app launches a
new activity. As task ID alone doesn't fully distinguish user or app
intent, this is considered an acceptable trade-off for improved bubble
behavior and the infrequency of such occurrences.

Bug: 390047887
Flag: EXEMPT bug fix
Test: atest WMShellUnitTests:BubblesTransitionObserverTest
Change-Id: I6c5ab588a41ecf096df0e6ea241a0151510570f6