Small optimization to not compute the highest version when it isn't d…

…isplayed

We added a setting about whether to show this to the user or not,
but always calculated the data regardless of the setting.

readthedocs/api/v2/views/footer_views.py

@@ -26,6 +26,8 @@ def get_version_compare_data(project, base_version=None):
     :param base_version: We assert whether or not the base_version is also the
                          highest version in the resulting "is_highest" value.
     """
+    if not project.show_version_warning:
+        return {'is_highest': False}
     versions_qs = Version.internal.public(project=project)
 
     # Take preferences over tags only if the project has at least one tag