Do not send (LOCKED_)BOOT_COMPLETED to private space apps.

These broadcasts wake up a ton of pre-installed apps whenever the
private profile is unlocked, causing jank and significant memory usage.

There are no ordering or timing guarantees around BOOT_COMPLETED, and
its use in a profile like private space is very limited anyway.
Therefore, defer delivering these broadcasts until an app is started the
first time since private space has unlocked.

Bug: 294192700
Test: Verify broadcasts being deferred, and then delivered (once)
Change-Id: I905d5afda2abb27c1a1beb18b3dcb5c0b44717ab