'Prettify query' causes many wrong transformations to the JSON

[maxb]

1. Create a simple dashboard, containing a single timeseries panel, querying a single metric - my MetricsQL was simply shelf_fan_labels.
2. Save dashboard.
3. Click 'Prettify query' button.
4. Click to save the dashboard and review the JSON changes about to be saved

The in-Grafana diff of the JSON changes is not presented well, so I pulled the relevant parts out to JSON files and diffed them manually...

--- targets1.json       2025-01-10 14:03:51.913508789 +0000
+++ targets2.json       2025-01-10 14:04:14.499938871 +0000
@@ -1,14 +1,23 @@
 {
   "targets": [
     {
-      "datasource": {
-        "type": "victoriametrics-datasource",
-        "uid": "PC4C83B0CAD5B2BCA"
-      },
-      "editorMode": "code",
+      "0": "s",
+      "1": "h",
+      "2": "e",
+      "3": "l",
+      "4": "f",
+      "5": "_",
+      "6": "f",
+      "7": "a",
+      "8": "n",
+      "9": "_",
+      "10": "l",
+      "11": "a",
+      "12": "b",
+      "13": "e",
+      "14": "l",
+      "15": "s",
       "expr": "shelf_fan_labels",
-      "legendFormat": "__auto",
-      "range": true,
       "refId": "A"
     }
   ]

The 'Prettify query' operation:

• Added a bizarre extra representation of the query in lots of single-character strings
• Deleted various other settings, which included functionally changing the legend from 'Auto' to 'Verbose' mode

It shouldn't be doing any of that.