perf/CI: Fix label condition

Author: peaBerberian

.github/workflows/perfs.yml

@@ -11,7 +11,7 @@ concurrency:
 
 jobs:
   perf-tests:
-    if: "!contains(github.event.issue.labels.*.name , 'skip-performance-checks')"
+    if: ${{ !contains(github.event.pull_request.labels.*.name, 'skip-performance-checks') }}
     runs-on: [ubuntu-latest]
     permissions:
       pull-requests: write