Fix zap command

congrats on the gitlab instance... shame it's not a sourcehut instance, because sending patches via email is much more convenient

anyway, end rant.

This patch fixes a bug

mrtest zap
Traceback (most recent call last):
  File "/usr/bin/mrtest", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/usr/lib/python3.12/site-packages/mrtest/frontend.py", line 76, in main
    origin = mrtest.origin.aports if args.alpine else mrtest.origin.pmaports
                                     ^^^^^^^^^^^
AttributeError: 'Namespace' object has no attribute 'alpine'

mrtest/frontend.py

@@ -77,10 +77,11 @@ def main() -> None:
     args = parse_args()
     if args.verbose:
         logging.getLogger().setLevel(logging.DEBUG)
+    if args.action == "zap":
+        mrtest.zap_packages.zap_packages()
+        return
     origin = mrtest.origin.aports if args.alpine else mrtest.origin.pmaports
     if args.action == "add":
         mrtest.add_packages.add_packages(origin, args.mr_id, args.no_cache)
     elif args.action == "upgrade":
         mrtest.upgrade_packages.upgrade_from_mr(origin, args.mr_id, args.alpine, args.available)
-    elif args.action == "zap":
-        mrtest.zap_packages.zap_packages()