[BE] Stop monitoring builder job status (#6929)

This repo is deprecated, don't monitor it for alerts any longer

Author: ZainRizvi

.github/workflows/check-alerts.yml

@@ -25,10 +25,6 @@ jobs:
             branch: nightly
             with_flaky_test_alerting: NO
             job_filter_regex: ""
-          - repo: pytorch/builder
-            branch: main
-            with_flaky_test_alerting: NO
-            job_filter_regex: ".*nightly.pypi.binary.size.validation|cron / release /"
     env:
       REPO_TO_CHECK: ${{ matrix.repo }}
       BRANCH_TO_CHECK: ${{ matrix.branch }}