Fix: [CI] preview for one PR could cancel the preview of another (#11121)

.github/workflows/preview-build.yml

@@ -10,10 +10,6 @@ on:
         description: Account ID to upload a preview to Cloudflare Pages
         required: true
 
-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
-  cancel-in-progress: true
-
 jobs:
   preview:
     name: Build preview

.github/workflows/preview.yml

@@ -8,6 +8,10 @@ on:
     branches:
     - master
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
 jobs:
   preview:
     if: ${{ (github.event.action == 'labeled' && github.event.label.name == 'preview') || (github.event.action != 'labeled' && contains(github.event.pull_request.labels.*.name, 'preview')) }}