Bar chart panel: x axis rotation leaves whitespace unused

### What happened? When changing the x axis tick rotation, the bar chart became smaller in height, leaving a portion of the panel unused. <img width="705" height="611" alt="Image" src="https://github.com/user-attachments/assets/a502d715-7c86-4aea-a07b-ba7c3c1c789a" /> ### What did you expect to happen? The x axis ticks get rotated with no (or only minimal) impact on the height of the chart. ### Did this work before? Yes, this issue showed up after an upgrade from v9.3.2 to v12.2.1. ### How do we reproduce it? 1. Create a bar chart with some dummy data in it. 2. Make sure the dummy data includes a column with a long string. Without this, the issue is not triggered. The longer the string, the worse it manifests. 3. Set orientation to vertical 4. Set "Rotate x-axis tick labels" to a non zero value. There is now a whitespace area below the bar chart that should not be there. Workaround: Set "X-axis tick label max length" to a low value. The whitespace is now gone again. This seems to indicate there is an issue with the x axis tick label length where the max length is kept free by the visualization even if the ticks don't actually take that much space. Reproduced on Grafana 12.3.0: - panel with no rotation -> no issue: [rotation 0.json](https://github.com/user-attachments/files/24009758/rotation.0.json) - panel with rotation -> too much whitespace: [rotation -45.json](https://github.com/user-attachments/files/24009759/rotation.-45.json) ### Is the bug inside a dashboard panel? | Key | Value | |--|--| | Panel | barchart @ 12.3.0 | | Grafana | Grafana v12.3.0 (20051fb1fc) // Open Source | <details><summary>Panel debug snapshot dashboard</summary> ```json { "panels": [ { "id": 2, "type": "barchart", "title": "Reproduced with embedded data", "gridPos": { "h": 13, "w": 15, "x": 0, "y": 0 }, "fieldConfig": { "defaults": { "custom": { "lineWidth": 1, "fillOpacity"…