fix: Explicitly convert child dictionary to json

ansible/roles/firstboot/files/ansible_payload/bootstrap/roles/metacluster/tasks/json-server.yml

@@ -7,7 +7,15 @@
         create_namespace: true
         wait: false
         kubeconfig: "{{ kubeconfig.path }}"
-        values: "{{ components['json-server'].chart_values }}"
+        values: |
+          {{
+            components['json-server'].chart_values |
+            combine( {
+              'seedData': {
+                'configInline': ( components['json-server'].chart_values.seedData.configInline | to_json )
+              }
+            } )
+          }}
 
     - name: Ensure json-server API availability
       ansible.builtin.uri: