Modernize file.module forms

Can we update the title about what's being accomplished here.

Thanks but think the actual title needs to updated.

looking in the file module there appear to be other test forms if we are just adding typehints?

I've updated the title.
I did a search and didn't found additional instances except one kernel test which we can't update

grep -r 'implements FormInterface' core/modules/file/tests

Should be fine then