[REF] Cleanup function for retrieving contact types.

[REF] Cleanup function for retrieving contact types.

This switches to using the apiv4 as part of trying to eliminate calls to executeQuery where the DAO is passed in
like

```
       = CRM_Core_DAO::executeQuery(, [],
        FALSE, 'CRM_Contact_DAO_ContactType'
      );
```

Note that this file seems to be the only place this is done.

Also note that I added tests first & the changes to the test highlight what is changed in the PR in the output - namely
- stricter type casting (courtesy apiv4)
- same keys present for all types