Limit the number of concurrently snoozed notifications

Test: atest FrameworksUiServicesTests
Bug: 234441463
Change-Id: I005b43979d1c708fd505c8b33ae0c8cb03ddbb35
Merged-In: I005b43979d1c708fd505c8b33ae0c8cb03ddbb35
(cherry picked from commit 7c38394ae9c69620499a87e629edae4fe0ac4edc)
(cherry picked from commit bc808de2f8a88e76fde0b6d033b4a232aebff8cb)
Merged-In: I005b43979d1c708fd505c8b33ae0c8cb03ddbb35
4 files changed