Update YDB SLO action to specific commit hash

Author: vgvoleg

.github/workflows/slo.yml

@@ -100,7 +100,7 @@ jobs:
           python -m pip install --no-cache-dir -r tests/slo/requirements.txt
 
       - name: Initialize YDB SLO
-        uses: ydb-platform/ydb-slo-action/init@main
+        uses: ydb-platform/ydb-slo-action/init@53e02500d4a98a6b67d9009bc46e839236f15f81
         with:
           github_pull_request_number: ${{ github.event.inputs.github_pull_request_number }}
           github_token: ${{ secrets.GITHUB_TOKEN }}