Replace generic radio button with GitLab UI styled radio button in app/views/projects/project_templates/_template.html.haml

The HAML template app/views/projects/project_templates/_template.html.haml contains a reference to %input{ type: "radio" } which renders a vanilla radio button element. We want to migrate these to the styled radio buttons defined in the Pajamas design system.

There are rails helpers for radios and checkboxes which will generate these styled elements for you in the context of a form. You can read their documentation here.

Outside of a form context, this pajamas DOM structure can be generated manually, or we may consider creating a generic HAML helper method for this purpose.

Migration notes will appear in the associated epic (&7971)