TEMP: Use custom image for test

Author: seunghun1ee

.github/workflows/stackhpc-multinode.yml

@@ -19,6 +19,9 @@ name: Multinode
           - rocky
           - ubuntu-jammy
           - ubuntu-noble
+      host_image_override:
+        description: Image name to override SKC defined default image
+        type: string
       neutron_plugin:
         description: Neutron ML2 plugin
         type: choice
@@ -64,6 +67,7 @@ jobs:
       os_release: ${{ inputs.os_distribution == 'rocky' && '9' || 'jammy' }}
       ssh_username: ${{ inputs.os_distribution == 'rocky' && 'cloud-user' || 'ubuntu' }}
       neutron_plugin: ${{ inputs.neutron_plugin }}
+      multinode_image_override: ${{ inputs.host_image_override }}
       upgrade: ${{ inputs.upgrade }}
       break_on: ${{ inputs.break_on }}
       # Workaround loss of number type using fromJSON: https://github.com/orgs/community/discussions/67182