dashboards/victorialogs: allow multiple values for instance variable (#7465)

### Describe Your Changes

Related issue https://github.com/VictoriaMetrics/helm-charts/issues/1699

### Checklist

The following checks are **mandatory**:

- [ ] My change adheres [VictoriaMetrics contributing
guidelines](https://docs.victoriametrics.com/contributing/).

dashboards/victorialogs.json

@@ -2816,8 +2816,8 @@
         },
         "definition": "label_values(vm_app_version{job=~\"$job\"}, instance)",
         "hide": 0,
-        "includeAll": false,
-        "multi": false,
+        "includeAll": true,
+        "multi": true,
         "name": "instance",
         "options": [],
         "query": {
@@ -2853,4 +2853,4 @@
   "uid": "OqPIZTX4z",
   "version": 1,
   "weekStart": ""
-}
+}