Gate the FGS timeout ANR behavior.

When this new flag is enabled, allow time-limited foreground services to
start even after they hit the timeout and don't throw an ANR either if
the service isn't stopped after the grace period.

Bug: 339315145
Test: atest CtsFgsTimeoutTestCases
Flag: android.app.gate_fgs_timeout_anr_behavior
Change-Id: I1bbe5447ca2f0450ac709b14f6577bacd9cf4bad