PasswordPolicy.getMinMetrics PIN

* If the password quality is NUMERIC
  or NUMERIC_COMPLEX, the credential
  type should be CREDENTIAL_TYPE_PIN

Bug: 184103377
Test: atest com.android.server.devicepolicy.PasswordPolicyTest
      make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.password
      CtsVerifier > Device owner tests > policy transparency test
      > set password quality
Change-Id: If0b1fbc71bbd0b4e59bc05594cd14e99a32d8bd1