Ensure that feeds are appropriately restricted (#10018)

* Always limit results by what is accessible to the user

* Change signature of AccessibleRepoIDsQuery

* Ensure that user with ID <= 0 is handled

* Update models/repo_list.go

models/action.go

@@ -312,8 +312,8 @@ func GetFeeds(opts GetFeedsOptions) ([]*Action, error) {
 		}
 
 		cond = cond.And(builder.In("repo_id", repoIDs))
-	} else if opts.Actor != nil {
-		cond = cond.And(builder.In("repo_id", opts.Actor.AccessibleRepoIDsQuery()))
+	} else {
+		cond = cond.And(builder.In("repo_id", AccessibleRepoIDsQuery(opts.Actor)))
 	}
 
 	cond = cond.And(builder.Eq{"user_id": opts.RequestedUser.ID})