Temp: Use rabbitmq CI testing branch

Author: seunghun1ee

.github/workflows/stackhpc-multinode.yml

@@ -70,6 +70,6 @@ jobs:
       ssh_key: ${{ inputs.ssh_key }}
       stackhpc_kayobe_config_version: ${{ github.ref_name }}
       # NOTE(upgrade): Reference the PREVIOUS and CURRENT releases here.
-      stackhpc_kayobe_config_previous_version: ${{ inputs.upgrade == 'major' && 'caracal-ca-choice' || 'stackhpc/2025.1' }}
+      stackhpc_kayobe_config_previous_version: ${{ inputs.upgrade == 'major' && 'rabbitmq-migration-ci' || 'stackhpc/2025.1' }}
       terraform_kayobe_multinode_version: ${{ inputs.terraform_kayobe_multinode_version }}
     secrets: inherit