Use clone_url for remote repository field (#11564)

This is currently using `str()` which renders the website URL. This is
fine for public repositories, but private repositories use the clone_url
as the project repo_url, so this field feels better matching that.

- Fixes #11562

Author: agjohnson

readthedocs/projects/forms.py

@@ -90,7 +90,7 @@ def _get_remote_repository_choices(self):
         if current_remote_repo and current_remote_repo not in queryset:
             options.append((current_remote_repo.pk, str(current_remote_repo)))
 
-        options.extend((repo.pk, str(repo)) for repo in queryset)
+        options.extend((repo.pk, repo.clone_url) for repo in queryset)
         return options
 
     def save(self, commit=True):