devops: fix test triggering (#5458)

Author: aslushnikov

.github/workflows/trigger_tests.yml

@@ -15,7 +15,7 @@ jobs:
         curl -X POST \
           -H "Accept: application/vnd.github.v3+json" \
           -H "Authorization: token ${GH_TOKEN}" \
-          --data '{"event_type": "playwright_tests", "client_payload": {"foo": "${GITHUB_SHA}"}}' \
+          --data "{\"event_type\": \"playwright_tests\", \"client_payload\": {\"ref\": \"${GITHUB_SHA}\"}}" \
           https://api.github.com/repos/microsoft/playwright-internal/dispatches
       env:
         GH_TOKEN: ${{ secrets.REPOSITORY_DISPATCH_PERSONAL_ACCESS_TOKEN }}