Move setCeStorageProtection() and unlockCeStorage() to StorageManagerInternal

Move these methods from IStorageManager to StorageManagerInternal, since
they are used only within system_server itself.

Update UserControllerTest#testUserNotUnlockedBeforeAllowed() to verify
that LockPatternUtils#unlockUserKeyIfUnsecured() was not called, instead
of verifying that StorageManager#unlockCeStorage() was not called.  This
matches the method that UserController actually calls.

Bug: 434738842
Flag: EXEMPT refactor
Test: atest FrameworksServicesTests:com.android.server.locksettings
Test: atest FrameworksServicesTests:UserControllerTest
Change-Id: I7b730f4d2c22db01debe575a31236da86f6ccdbb