Addons: small improvements and privacy considerations (#11561)

- We had a special case in a permissions class, I moved this into the view itself.
- We are allowing some requests to not have a version, so our normal permission check doesn't work in this case. In case that we don't have a version, we just check for the project permission.
- If we have a version, we are attaching its latest build, this code was duplicated, and wasn't taking into considerations permissions. In case of temporal sharing tokens, they don't have access to builds.
- Translations now take into consideration the current user permissions
- The list of active versions can now be overridden from .com to include versions granted by a temporal access.

Some notes:

- We are returning some custom 404 responses, but DRF already handles that when using get_object_or_404. Anyway, users won't see any of the messages, since our 404 handler is catching those in production.
- Returning the full serialized version of translations takes like 40 extra queries, probably it generates more per extra translation. From what I found, most of the queries are due to the serializer returning more related projects fully serialized (main translation, superproject).
- We are allowing users to override the whole response, we should just allow to override the `addons` key.
- This also suffers from readthedocs/readthedocs-corporate#1845

Since to really run the whole code from permissions checks organizations are needed, I'll add tests on .com. 

ref readthedocs/readthedocs-corporate#1773

readthedocs/api/v2/permissions.py

@@ -40,17 +40,6 @@ class IsAuthorizedToViewVersion(permissions.BasePermission):
     def has_permission(self, request, view):
         project = view._get_project()
         version = view._get_version()
-
-        # I had to add this condition here because I want to return a 400 when
-        # the `project-slug` or `version-slug` are not sent to the API
-        # endpoint. In those cases, we don't have a Project/Version and this
-        # function was failing.
-        #
-        # I think it's a valid use case when Project/Version is invalid to be
-        # able to return a good response from the API view.
-        if project is None or version is None:
-            return True
-
         has_access = (
             Version.objects.public(
                 user=request.user,

readthedocs/proxito/tests/test_hosting.py

@@ -19,7 +19,6 @@
     SINGLE_VERSION_WITHOUT_TRANSLATIONS,
 )
 from readthedocs.projects.models import AddonsConfig, Domain, Project
-from readthedocs.proxito.views.hosting import ClientError
 
 
 @override_settings(
@@ -284,6 +283,7 @@ def test_flyout_translations(self):
             slug="translation",
             main_language_project=self.project,
             language="ja",
+            privacy_level=PUBLIC,
         )
         translation_ja.versions.update(
             built=True,
@@ -530,20 +530,24 @@ def test_flyout_subproject_urls(self):
             slug="translation",
             language="es",
             repo="https://github.com/readthedocs/subproject",
+            privacy_level=PUBLIC,
         )
         translation.versions.update(
             built=True,
             active=True,
         )
         subproject = fixture.get(
-            Project, slug="subproject", repo="https://github.com/readthedocs/subproject"
+            Project,
+            slug="subproject",
+            repo="https://github.com/readthedocs/subproject",
+            privacy_level=PUBLIC,
         )
         self.project.add_subproject(subproject)
         subproject.translations.add(translation)
         subproject.save()
 
-        fixture.get(Version, slug="v1", project=subproject)
-        fixture.get(Version, slug="v2.3", project=subproject)
+        fixture.get(Version, slug="v1", project=subproject, privacy_level=PUBLIC)
+        fixture.get(Version, slug="v2.3", project=subproject, privacy_level=PUBLIC)
         subproject.versions.update(
             privacy_level=PUBLIC,
             built=True,
@@ -710,9 +714,7 @@ def test_non_existent_project(self):
             },
         )
         assert r.status_code == 404
-        assert r.json() == {
-            "error": ClientError.PROJECT_NOT_FOUND,
-        }
+        assert r.json() == {"detail": "No Project matches the given query."}
 
     def test_number_of_queries_project_version_slug(self):
         # The number of queries should not increase too much, even if we change
@@ -734,7 +736,7 @@ def test_number_of_queries_project_version_slug(self):
                 active=True,
             )
 
-        with self.assertNumQueries(23):
+        with self.assertNumQueries(22):
             r = self.client.get(
                 reverse("proxito_readthedocs_docs_addons"),
                 {
@@ -825,7 +827,7 @@ def test_number_of_queries_url_translations(self):
                 language=language,
             )
 
-        with self.assertNumQueries(56):
+        with self.assertNumQueries(60):
             r = self.client.get(
                 reverse("proxito_readthedocs_docs_addons"),
                 {