t/main/services-user: typo fix

tests/main/services-user/task.yaml

@@ -52,7 +52,7 @@ execute: |
     tests.session -u test exec systemctl --user is-active snap.test-snapd-user-service.svc2.service | MATCH "inactive"
 
     # if non-root are making requests, and user services are the target,
-    # then its an error to not specifiy --user scope
+    # then its an error to not specify --user scope
     echo "(user) Trying to start services for snap, which will fail with no scope set"
     tests.session -u test exec snap start test-snapd-user-service 2>&1 | MATCH "a service scope must be provided"