Remove LockSettingsInternal from LockPatternUtils

LockPatternUtils is a utility class shared by system_server, Settings,
SystemUI, and other system processes.  Yet, some of its methods use
LockSettingsInternal.  These methods only work in system_server.
Callers of these methods should just use LockSettingsInternal directly.

Therefore, update all such callers to do just that.  Then remove the
LockPatternUtils versions of these methods.

No change in behavior intended, but a couple details worth calling
attention to:

- LockPatternUtils#setLockCredentialWithToken() had some extra code
  before it called into LockSettingsInternal.  I moved that into
  LockSettingsInternal, which already contained nearly the same code.

- UserManagerService now caches the LockSettingsInternal, like it does
  with the other local services.  LockPatternUtils did not cache it.

Bug: 408077877
Test: atest Frameworks{,Mocking}ServicesTests:com.android.server.{devicepolicy,locksettings,recoverysystem,trust}
Test: atest Frameworks{,Mocking}CoreTests:com.android.internal.widget
Flag: EXEMPT refactor
Change-Id: I72ddc018a0747f7914542bdebbec1d2a2f6bfcac