PHP 8 incompatibility using retrieval of defaults with multi entry custom fields

There is a incompability with PHP 8 and Caldera Forms if one tries to use the retrieval of defaults to pull data of a custom field with multi entries, such as e.g. checkboxes.

The errors occurs in the class member function 'find_tags()' of the class 'Caldera_Forms_Sync_Sync'.

To my understanding this function tries to check, wether the default values of the field contain any magic tags e.g. '%some_slug%' using the PHP function 'preg_match_all'. However, if one uses retrieval of defaults to pull data of a custom field with multi entries, the default value is not a string, as expected, but an array of strings. This seems to throw an error in PHP8 (not sure why this was possible in PHP 7.4).

An easy fix would be to simply skip the check, if the default value is an array or not a string. Within my development-environment this fixed the incompability and I am happy to provide a merge request with such a fix.

However, I am not sure, if this creates any unwanted sides effects, that I am not aware of. Would be glad about some feedback.