Geomap: marker color by time does not seem to range correctly

### What happened? When coloring markers by time with a red-yellow-green colorscheme, the time range doesn't seem to get set based on the min/max timestamp of the datapoints: <img width="725" alt="Image" src="https://github.com/user-attachments/assets/39cfc08e-1c71-4dd3-b7b5-85d8f9d037bb" /> data in table view: ### What did you expect to happen? The marker colors to vary across the min/max timestamp, like they do when, e.g. coloring by latitude: <img width="726" alt="Image" src="https://github.com/user-attachments/assets/ace16141-5650-41f4-a20c-521d90c5805f" /> ### Did this work before? unsure, first time trying ### How do we reproduce it? 1. get some lat/long datapoints into a geomap 2. set marker style color by time 3. view the map ### Is the bug inside a dashboard panel? | Key | Value | |--|--| | Panel | geomap @ 11.3.2 | | Grafana | Grafana v11.3.2 (NA) // Open Source | <details><summary>Panel debug snapshot dashboard</summary> ```json { "panels": [ { "id": 2, "type": "geomap", "title": "Reproduced with embedded data", "description": "", "gridPos": { "h": 13, "w": 15, "x": 0, "y": 0 }, "fieldConfig": { "defaults": { "custom": { "hideFrom": { "tooltip": false, "viz": false, "legend": false } }, "mappings": [], "thresholds": { "mode": "absolute", "steps": [ { "color": "green", "value": null } ] }, "color": { "mode": "continuous-RdYlGr" }, "fieldMinMax": false }, "overrides": [] }, "transformations": [ { "id": "merge", "options": {} } ], "pluginVersion": "11.3.2", "targets": [ { "refId": "A", "datasource": { "…