Revert "workflows: Ensure a label change re-triggers the actions"

This reverts commit 7a879164bd, as it's
been proved that re-triggering the checks at every single change is more
painful than having to close / re-open a PR in case we ever use the
`force-skip-ci` label again.

Fixes: #2804

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

.github/workflows/snap.yaml

@@ -6,8 +6,6 @@ on:
       - synchronize
       - reopened
       - edited
-      - labeled
-      - unlabeled
 
 jobs:
   test: