ci: use default-pipeline check for gitlab status rather than custom scripts

.github/workflows/all-checks.yml

@@ -16,4 +16,4 @@ jobs:
                 delay: '3'
                 retries: '45'
                 polling_interval: '1'
-                checks_exclude: 'devflow/merge'
+                checks_exclude: 'devflow/merge,dd-gitlab/default-pipeline'

.gitlab-ci.yml

@@ -21,28 +21,3 @@ trigger_internal_build:
     project: DataDog/apm-reliability/libddprof-build
     strategy: depend
     branch: $DOWNSTREAM_BRANCH
-
-# Following jobs are required otherwise gitsync will not report downstream pipeline failure to github
-
-# This job is used to determine if downstream pipeline has succeeded
-report_failure:
-  tags: ["arch:amd64"]
-  when: on_failure
-  needs: [trigger_internal_build, benchmarks]
-  # allow_failure: true prevents the job from showing up in github statuses (because it's filtered by gitsync)
-  allow_failure: true
-  script:
-    - echo "STATUS=1" >> .env
-    - exit 1 # if this job completes it should always be considered a failure
-  artifacts:
-    reports:
-      dotenv: .env
-
-# Final job that will show in github statuses
-report_gitlab_CI_status:
-  tags: ["arch:amd64"]
-  when: always
-  stage: .post
-  script:
-    - "echo TIP: If you see this failing, something else in the GitLab pipeline failed. Follow the link to the pipeline and check for other things that failed prior to this step."
-    - exit ${STATUS}