Clarify that data source request reports are not for bugs or support requests (#90661)

Co-authored-by: David Harris <david.harris@grafana.com>

.github/ISSUE_TEMPLATE/3-data_source_request.yaml

@@ -15,6 +15,10 @@ body:
         Grafana Labs regularly reviews these requests and uses them to inform our prioritization. Note: we cannot offer any guarantees on whether we or our community will build a given data source.
         
         Please check our [roadmap](https://github.com/orgs/grafana/projects/619?pane=info) for existing requests and subscribe to stay informed of our plans. If no request exists, please fill out the following information.
+
+        Please do not request support or file bug reports and feature requests for existing plugins here.
+        - For support, please use the community support resources [here](https://grafana.com/help/).
+        - Please consider the `New Bug Report` or `Feature Requests` [issue templates](https://github.com/grafana/grafana/issues/new/choose) for other requests.
   - type: textarea
     id: background
     attributes: