PHP 8 fix when contact doesn't exist
Created by: MegaphoneJon
When submitting "Update Comms Preferences" on a contact that doesn't currently exist, this error appears:
TypeError: array_fill_keys(): Argument #1 ($keys) must be of type array, string given in array_fill_keys() (line 523 of /mysite/web/sites/all/civicrm-custom/extensions/uk.co.vedaconsulting.gdpr/CRM/Gdpr/CommunicationsPreferences/Utils.php)
That's because of stricter PHP type checking in PHP8, this is a fix.