Don't ret admin info from createAdminSupportIntent

As part of fixing the security vulnerability(b/192245204), do not
return admin package details in the returned
Intent(ACTION_SHOW_ADMIN_SUPPORT_DETAILS) from createAdminSupportIntent
API. Insted introduce an API to return admin info given user and
restriction, this API will be used by the Activity that handles the
Intent returned by createAdminSupportIntent API.

Bug: 192245204
Test: atest MixedDeviceOwnerTest#testCreateAdminSupportIntent
      atest MixedProfileOwnerTest#testCreateAdminSupportIntent
      atest MixedManagedProfileOwnerTest#testCreateAdminSupportIntent
      atest DevicePolicyManagerTest#testCreateAdminSupportIntent

Change-Id: I3ed502a078eebac62e0b8a27f6302410c22111e4
Merged-In: I3ed502a078eebac62e0b8a27f6302410c22111e4