ref: fix mypy cache breakage with WithAnnotations (#56961)

I am surprised mypy lets me do this without a cast but shrugs...

this hacks around the cache being poisoned by:

```
AssertionError: Cannot find component 'WithAnnotations[sentry__models__commitauthor__CommitAuthor]' for 'django_stubs_ext.WithAnnotations[sentry__models__commitauthor__CommitAuthor]'
```

src/sentry/api/endpoints/organization_missing_org_members.py

@@ -28,7 +28,9 @@ from sentry.search.utils import tokenize_query
 from sentry.services.hybrid_cloud.integration import integration_service
 
 if TYPE_CHECKING:
-    from django_stubs_ext import WithAnnotations
+    # XXX: this should use WithAnnotations but it breaks the cache typeddjango/django-stubs#760
+    class CommitAuthor___commit__count(CommitAuthor):
+        commit__count: int
 
 
 filtered_email_domains = {
@@ -53,7 +55,7 @@ class MissingMembersPermission(OrganizationPermission):
 
 def _get_missing_organization_members(
     organization: Organization, provider: str, integration_ids: Sequence[int]
-) -> QuerySet[WithAnnotations[CommitAuthor]]:
+) -> QuerySet[CommitAuthor___commit__count]:
     member_emails = set(
         organization.member_set.exclude(email=None).values_list("email", flat=True)
     ) | set(organization.member_set.exclude(user_email=None).values_list("user_email", flat=True))