grafana: Replace deprecated apt_key with get_url

grafana/tasks/main.yml

 ---
 
 - name: Install Grafana repository keys
-  apt_key:
+  ansible.builtin.get_url:
     url: https://packages.grafana.com/gpg.key
-    state: present
+    dest: /etc/apt/trusted.gpg.d/grafana.asc
+    force: true
+    owner: root
+    group: root
+    mode: "0644"
   tags:
     - packages
     - repo