fix(pre-pull-images): use ubuntu-latest for certain steps

.github/workflows/pre-pull-images.yaml

@@ -14,7 +14,7 @@ concurrency:
 jobs:
   changed-clusters:
     name: Changed Clusters
-    runs-on: ["gha-runner-scale-set"]
+    runs-on: ubuntu-latest
     outputs:
       matrix: ${{ steps.changed-clusters.outputs.all_changed_and_modified_files }}
     steps:
@@ -46,7 +46,7 @@ jobs:
 
   extract-images:
     name: Extract Images
-    runs-on: ["gha-runner-scale-set"]
+    runs-on: ubuntu-latest
     needs: ["changed-clusters"]
     permissions:
       pull-requests: write
@@ -164,7 +164,7 @@ jobs:
     if: ${{ always() }}
     needs: ["pre-pull-images"]
     name: Pre-pull Images Successful
-    runs-on: ["gha-runner-scale-set"]
+    runs-on: ubuntu-latest
     steps:
       - if: ${{ contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled') }}
         name: Check matrix status