Containerd registries config not live

I found a bug where my custom containerd registries config wasn't live,
despite the correct `notify` handlers being specified in the
'Ensure containerd registries file exists' task.

This change fixes that by ensuring the handlers get triggered.

tasks/state_installed.yml

@@ -44,3 +44,6 @@
     - k3s_build_cluster is defined
     - k3s_build_cluster
     - k3s_registration_address is defined
+
+- name: Flush Handlers
+  ansible.builtin.meta: flush_handlers