[CI] Do not run the workflow in forks (#20359)

Author: KornevNikita

.github/workflows/sycl-check-ready-to-merge-prs.yml

@@ -14,6 +14,7 @@ permissions: read-all
 
 jobs:
   notify-ready-prs:
+    if: github.repository == 'intel/llvm'
     permissions:
       pull-requests: write
     runs-on: ubuntu-latest