[Android] Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent.

Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent. Strongly consider using FLAG_IMMUTABLE, only use FLAG_MUTABLE if some functionality depends on the PendingIntent being mutable, e.g. if it needs to be used with inline replies or bubbles.