Add influxdb namespace to identify version (#6044)

Add influxdb namespace to identify current InfluxDB Clustered package version, which matches the influxdb namespace example used to apply the updated image.

Co-authored-by: Scott Anderson <sanderson@users.noreply.github.com>

Author: abalone23

content/influxdb3/clustered/admin/upgrade.md

@@ -51,7 +51,7 @@ Use the following command to return the image Kubernetes uses to build your
 InfluxDB cluster:
 
 ```sh
-kubectl get appinstances.kubecfg.dev influxdb -o jsonpath='{.spec.package.image}'
+kubectl get appinstances.kubecfg.dev influxdb -n influxdb -o jsonpath='{.spec.package.image}'
 ```
 
 The package version number is at the end of the returned string (after `influxdb:`):