[Stat Visualisation] String FAILURE breaks the stat counter

### What happened? When using the stat visualisation with querying on an actual opensearch ` message.result: "SUCCESS" or message.result: "FAILURE" ` only the SUCCESS gets a count number, FAILURE dont. And yes there is data with FAILURE. Queryinspector shows me a different escaping ` \"query\":\"message.result: \\\"(\\\"FAILURE\\\") \"query\":\"message.result: \\\"SUCCESS\\\"\"}}]} ` The timeline the the stat visualisation shows me there is data <img width="1913" height="955" alt="Image" src="https://github.com/user-attachments/assets/732c98c5-deb4-4cd8-b673-0e131bce5680" /> It looks, the string FAILURE is handled in a special manner wich breaks the stat visualisation counter Grafana 12.1.1 ### What did you expect to happen? need advice to circumvent this behaviour or a fix ### Did this work before? it worked in the past, but many version before ### How do we reproduce it? 1. Query some string value: FAILURE in stat visualisation, evtl. specific opensearch / elasticsearch ### Is the bug inside a dashboard panel? Stat Visualisation ### Environment (with versions)? Grafana: 12.1.1 OS: Debian Gnu Linux 12 Browser: Librewolf ### Grafana platform? A package manager (APT, YUM, BREW, etc.) ### Datasource(s)? apt.grafana.com