Properly validate credential in setLock(int, byte[], int, byte[])

In KeyguardManager, one of the two overloads of setLock() properly
validates the new credential using the logic in PasswordMetrics, while
the other doesn't.  This appears to be an oversight, and it was allowing
a test to set a PIN containing invalid characters.  Fix this by always
calling PasswordMetrics#validateCredential() on the new credential.

Bug: 219511761
Bug: 232900169
Bug: 243881358
Test: atest android.app.KeyguardManagerTest
Test: atest android.app.cts.KeyguardManagerTest
Test: atest CtsSensorPrivacyTestCases # since it calls setLock()
Change-Id: I46d8bf920526a00d6e6d2145d06c8e39f8047ea8