fix: refine content extraction for Proxmox snippets storage configuration

tasks/preflight-checks.yml

@@ -171,7 +171,7 @@
     - name: "[PREFLIGHT] Get current content list of the target storage"
       ansible.builtin.shell: >
         awk '/^dir: {{ proxmox_snippets_storage }}/,/^$/' /etc/pve/storage.cfg |
-        awk '/content/ {print $3}'
+        awk '/content/ {sub(/^content[[:space:]]*/, ""); print}'
       register: current_content
       changed_when: false