Drilldown: Filtering traces by attributes with boolean values returns no data

### What happened? 1. Send one or more spans to Tempo with a resource attribute (let's call it `foo`) with value `true`. 2. Navigate to the Traces Drilldown view (`<domain>/a/grafana-exploretraces-app/explore?...`) 3. In "Filters", choose "All Spans" 4. In "Filter by label values", filter by the above attribute/value pair (i.e. `resource.foo` `=` `true`) 5. No data appears (see below) <img width="1302" height="951" alt="Image" src="https://github.com/user-attachments/assets/826161d3-04ec-4a4e-a591-8eca0aa8d5c1" /> Switching the operator to `=~` while keeping the RHS as `true` fails with a 400 Bad Request error (see below) <img width="1302" height="789" alt="Image" src="https://github.com/user-attachments/assets/b3bc3a9c-5033-4626-b90f-2c732e319cfe" /> ... but changing the RHS to `true$` works, suggesting that the UI is interpreting `true` as a boolean primitive instead of a string. <img width="1296" height="828" alt="Image" src="https://github.com/user-attachments/assets/f27d8dbf-6b64-4a8a-9299-90be1c90e553" /> ### What did you expect to happen? Data about the span(s) matching `resource.foo = true` appears. ### Did this work before? Unknown (not attempted in any other versions of Grafana) ### How do we reproduce it? See "What happened". ### Is the bug inside a dashboard panel? No ### Environment (with versions)? Grafana: v12.2.0-17142428006 (86aa5dca11) OS: macOS (Sequoia 15.5) Browser: Google Chrome 141.0.7390.66 (Official Build) (arm64) ### Grafana platform? Kubernetes ### Datasource(s)? Tempo