Use Pajamas button component for form submit in app/views/groups/_import_group_from_another_instance_panel.html.haml

One or more forms in app/views/groups/_import_group_from_another_instance_panel.html.haml have their submit button styled with CSS classes to make it look Pajamas-compliant.

Instead we can use the pajamas_button: true toggle on the f.submit to reduce CSS duplication and make the form use a ViewComponent for the submit button instead.

See the parent epic for guidance.

👉 This is probably a simple one-line change. Please do not create a Merge Request for this issue alone. Assign yourself up to 5 issues like this and fix them all in the same merge request. This way we save some reviewer time and CI minutes. Thank you!