Ignore pinned Windows

Pinned windows (e.g. PIP windows) should not enable BAL.

Test: atest BackgroundActivityLaunchTest BackgroundActivityStartController*Tests BackgroundLaunchProcessControllerTests
Flag: EXEMPT security fix
Bug: 406880479
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:accdba705e784ca8a90a62733e9ee44995d823b1)
Merged-In: I7ef4eb7123de24815703f4cc36cd192b6bca9517
Change-Id: I7ef4eb7123de24815703f4cc36cd192b6bca9517