ci: temporarily test only on amd64

Author: lengau

.github/workflows/qa.yaml

@@ -15,4 +15,9 @@ jobs:
   test:
     uses: canonical/starflow/.github/workflows/test-python.yaml@main
     with:
+      fast-test-platforms: '[["jammy", "amd64"], ["noble", "amd64"]]'
+      slow-test-platforms: '[["jammy", "amd64"], ["noble", "amd64"]]'
+      lowest-python-platform: '["jammy", "amd64"]'
       fast-test-python-versions: '["3.10", "3.12"]'
+      slow-test-python-versions: '["3.10", "3.12"]'
+      lowest-python-version: "3.10"