Fix Archivematica acceptance tests workflow

GitHub started running jobs marked with ubuntu-latest on Ubuntu 24.04
which breaks the AMAUATs workflow.

This pins the test job of the workflow to run on Ubuntu 22.04 due to
MySQL failures in Podman 4+ containers.

.github/workflows/archivematica-acceptance-tests.yml

@@ -22,7 +22,7 @@ on:
 jobs:
   test:
     name: "${{ matrix.feature }} / ${{ matrix.docker_image.label }}"
-    runs-on: "ubuntu-latest"
+    runs-on: "ubuntu-22.04"
     env:
       am_version: "${{ inputs.am_version || 'qa/1.x' }}"
       ss_version: "${{ inputs.ss_version || 'qa/0.x' }}"