Restricted datasource access via spoofed query type

Incorrect authorization in Grafana OSS and Enterprise allows remote authenticated users to query restricted datasources through alert rules. The alert-rule authorization path trusts the client-controlled queryType value expr and skips permission checks, but evaluation resolves the real datasourceUid and executes the query with Grafana's configured credentials. The user must belong to the same organization, be able to create or edit alert rules, know the datasource UID, and lack direct query permission; exposed credentials can permit data reads and, for some backends, writes.