[INTERNAL] enforce required email field

## Summary of changes

The proto for `user` was created before our annotation pattern was finalized. As a result it is too permissive. It make the `email` field optional, but it is actually required.

## Testing strategy

Borrow and tested in console-eng

GitOrigin-RevId: 6a23ceb82b50fd37691b10c8dd0e8f7e51eeb0e9

src/gretel_client/rest_v1/models/user_profile.py

@@ -35,7 +35,7 @@ class UserProfile(BaseModel):
     firstname: Optional[StrictStr] = None
     lastname: Optional[StrictStr] = None
     image: Optional[UserProfileImage] = None
-    email: Optional[StrictStr] = None
+    email: StrictStr
     __properties: ClassVar[List[str]] = [
         "id",
         "firstname",