GitHub Actions workflow 자동 실행 비활성화

- pull_request 트리거 주석 처리하여 PR 시 자동 실행 방지
- workflow_dispatch만 활성화하여 수동 실행만 가능하도록 변경

.github/workflows/backend-cicd.yaml

@@ -9,12 +9,12 @@ on:
   #     - '*-service/**'
   #     - '.github/workflows/backend-cicd.yaml'
   #     - '.github/kustomize/**'
-  pull_request:
-    branches:
-      - develop
-      - main
-    paths:
-      - '*-service/**'
+  # pull_request:
+  #   branches:
+  #     - develop
+  #     - main
+  #   paths:
+  #     - '*-service/**'
   workflow_dispatch:
     inputs:
       environment: