Grafana 11.3+: Variables of type Constant in Flux/InfluxQL queries lead to "No data" in visualisation

### What happened? After upgrade to 11.3.0 _Flux_ queries in dashboards stopped working when they were using variables. ### What did you expect to happen? Dashboards queries work as before. ### Did this work before? 11.2.2 with security fix and after the downgrade to 11.2.3 data is shown (again) ### How do we reproduce it? 1. Have a dashboard with a variable of type constant and a Flux query   2. This yields "No data" in the dashboard when adding the required variables to the URL 3. Changing the query to fixed values and it works (tested using "Explore" option of the datasource)  ### Is the bug inside a dashboard panel? _No response_ ### Environment (with versions)? Grafana: 11.3.0 OS: Ubuntu 22.04.5 Browser: Chrome ### Grafana platform? None ### Datasource(s)? InfluxDB v2.7.10