Always treat password as sufficient if no password policy is set

Handle the special case when work profile is freshly created on a FDE device

Test: cts-tradefed run cts-dev -m CtsDevicePolicyManagerTestCases
      -t com.android.cts.devicepolicy.MixedManagedProfileOwnerTest#testPasswordSufficientInitially
Bug: 63887564
Change-Id: Ie8e430d4ff63be74fb2d4fc3ad3a8735f1de48b0