Panels: Field Override Fields by Name is not found

### What happened? Issue: When creating a Transformation with the degree set to "Quartic", the panel only works in the language in which it was originally saved. Example: In English Grafana, the option appears as "Quartic Polynomial regression Total". In German Grafana, the option appears as "Quartisch Polynomial regression Total". Because the transformation relies on the localized field name, the panel fails when opened in a different language. Expected Behavior: Fields should be matched by a consistent value/identifier, not by the localized display name, so that panels work regardless of the Grafana language setting. <img width="1635" height="331" alt="Image" src="https://github.com/user-attachments/assets/8123b1ae-bc9f-405a-a2c5-c355087f8aaa" /> ### What did you expect to happen? getFieldNameMatcherItem seems to match fields by their name (localized string) rather than by a language-independent value. This makes the field resolution language-dependent instead of stable across locales. ### Did this work before? Yes ### How do we reproduce it? 1. Create a Trendline Transformation with Model-Type Polinominal and Degree Quartic 2. Create an override with this transformation using "Fields with Name" 3. Save Dashboard 4. Go to user profile and change the language 5. Open the dashboard again an the Trendline is no longer a trendline, instead it tries to create a barchart with the data from the trendline. ### Is the bug inside a dashboard panel? | Key | Value | |--|--| | Panel | timeseries @ 12.1.1 | | Grafana | Grafana v12.1.1 (df5de8219b) // Open Source | <details><summary>Panel debug snapshot dashboard</summary> ```json { "panels": [ { "id": 2, "type": "timeseries", "title": "Reproduced with embedded data", "gridPos": { "h": 13, "w": 15, "x": 0, "y": 0 }, "fieldConfig": { "defaults": { "custom": { "drawStyle": "line", "lineInterpolation": "linear", …