DO NOT MERGE Disallow Wallpaper service to launch activity from background.

Add a flag so that when a foreground client binds to a service,
disallow the bound service to launch activity from background.
Modify the WallpaperManagerService to take advantage of the new flag.

Test: atest BackgroundActivityLaunchTest WallpaperManagerServiceTests
Bug: 261072174
(cherry picked from commit 064be0ff)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:b7b2856de6258ee2595cc60b30e2e3c6648dfc74)
Merged-In: Id4e4cb6144597cf3638f2aaa34ea455a239fa1a7
Change-Id: Id4e4cb6144597cf3638f2aaa34ea455a239fa1a7