Sub panel install issue

I'd be seriously tempted to email that picture to the licensing board...

I assume from your question that this was installed, incorrectly, by licensed electricians.

Buy a ground bar to fit your panel, note the pre-threaded holes in the back of the panel for the ground bar, move the ground wire to it, and remove the bonding screw. Or call up your "licensed electricians" and have them come correct their error without charging you extra, because it was a blatant error.

You will need a torque screwdriver (or low-value inch-pound torque wrench) for the connections to the ground bar, and your breakers, and perhaps you need to check the torque on the screws installed by your "licensed electricians" as well.

Yeah, this was wrong

What the installers did here was a pretty blatant violation of the NEC 250.142(B) requirement that the grounded conductor not be used as a grounding means downstream of the service entrance, and doesn't fall under any of the exceptions that section provides. So, I'd make them fix it, as it shouldn't take them long to pick up the correct ground bar for your panel, whack it in there, move the green wire over to it, and remove the green grounding screw.

If you can't get them to come out there again, you'll need an Eaton GBKP14P, which you should be able to order in thru your local Lowes, or simply order online for that matter. Once you have that, the process is the same; just remember to keep the feeder breaker off until the work's done, though!