Navigation: Backend to save navigation customization into preferences (#89783)

docs/sources/developers/http_api/preferences.md

@@ -53,7 +53,7 @@ Content-Type: application/json
     "timezone": "utc",
     "weekStart": "",
     "navbar": {
-        "savedItems": null
+        "savedItemIds": null
     },
     "queryHistory": {
         "homeTab": ""
@@ -142,7 +142,7 @@ Content-Type: application/json
     "timezone": "",
     "weekStart": "",
     "navbar": {
-        "savedItems": null
+        "savedItemIds": null
     },
     "queryHistory": {
         "homeTab": ""