If pro is included in the theme then its features are probably required. You will either need to contact the developer for an update to the theme or you will have to buy a license and install it separately. If the developer did it correctly when you install the plugin on the site normally it should override the plugin in the theme. But you should still contact the developer of the theme because there isn’t any way to know if the theme will be compatible. You should probably contact theme and see if there is an updated theme available.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users