Update messenger consumer shell command for preserved environment variables

Replaced `su` with `su -p` in `compose.yaml` to ensure the environment variables of the parent shell are preserved when running the messenger consumer.

templates/config/prod/messenger.yaml

@@ -18,4 +18,4 @@ framework:
             priority: 'doctrine://default'
             {% endif +%}
             failed: 'doctrine://default?queue_name=failed'
-            sync: 'sync://'
+            sync: 'sync://'