fix(dashboards): Updates dashboard quota to not count prebuilt dashboards (#103985)

Filters out prebuilt dashboards when fetching count to check against
dashboard quota

Author: edwardgou-sentry

src/sentry/dashboards/endpoints/organization_dashboards.py

@@ -446,7 +446,9 @@ def post(self, request: Request, organization: Organization, retry: int = 0) ->
         if not features.has("organizations:dashboards-edit", organization, actor=request.user):
             return Response(status=404)
 
-        dashboard_count = Dashboard.objects.filter(organization=organization).count()
+        dashboard_count = Dashboard.objects.filter(
+            organization=organization, prebuilt_id=None
+        ).count()
         dashboard_limit = quotas.backend.get_dashboard_limit(organization.id)
         if dashboard_limit >= 0 and dashboard_count >= dashboard_limit:
             return Response(

tests/sentry/dashboards/endpoints/test_organization_dashboards.py

@@ -1893,6 +1893,36 @@ def test_dashboard_limit_prevents_creation(self, mock_get_dashboard_limit) -> No
         response = self.do_request("post", self.url, data={"title": "New Dashboard w/ Limit"})
         assert response.status_code == 201
 
+    @patch("sentry.quotas.backend.get_dashboard_limit")
+    def test_dashboard_limit_does_not_count_prebuilt_dashboards(
+        self, mock_get_dashboard_limit
+    ) -> None:
+        mock_get_dashboard_limit.return_value = 2
+
+        Dashboard.objects.create(
+            organization=self.organization,
+            title="Prebuilt Dashboard 1",
+            created_by_id=None,
+            prebuilt_id=1,
+        )
+        Dashboard.objects.create(
+            organization=self.organization,
+            title="Prebuilt Dashboard 2",
+            created_by_id=None,
+            prebuilt_id=2,
+        )
+
+        # 2 prebuilt + 2 user dashboards
+        response = self.do_request("post", self.url, data={"title": "Dashboard at Limit"})
+        assert response.status_code == 400
+        assert response.data == "You may not exceed 2 dashboards on your current plan."
+
+        self.dashboard.delete()
+
+        # 2 prebuilt + 1 user dashboard
+        response = self.do_request("post", self.url, data={"title": "New Dashboard w/ Prebuilt"})
+        assert response.status_code == 201
+
     def test_prebuilt_dashboard_is_shown_when_favorites_pinned_and_no_dashboards(self) -> None:
         # The prebuilt dashboard should not show up when filtering by owned dashboards
         # because it is not created by the user