[chore] enable running ARM builds by default (#38204)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
Run ARM builds on any PR.

<!-- Issue number (e.g. #1234) or full URL to issue, if applicable. -->
#### Link to tracking issue
Fixes #38198

Author: atoulme

.github/workflows/build-and-test-arm.yml

@@ -22,7 +22,7 @@ concurrency:
 
 jobs:
   arm-unittest-matrix:
-    if: ${{ github.actor != 'dependabot[bot]' && (contains(github.event.pull_request.labels.*.name, 'Run ARM') || github.event_name == 'push' || github.event_name == 'merge_group') }}
+    if: ${{ github.actor != 'dependabot[bot]' && (!contains(github.event.pull_request.labels.*.name, 'Skip ARM') || github.event_name == 'push' || github.event_name == 'merge_group') }}
     strategy:
       fail-fast: false
       matrix:
@@ -69,7 +69,7 @@ jobs:
       - name: Run Unit Tests
         run: make -j2 gotest GROUP=${{ matrix.group }}
   arm-unittest:
-    if: ${{ github.actor != 'dependabot[bot]' && (contains(github.event.pull_request.labels.*.name, 'Run ARM') || github.event_name == 'push' || github.event_name == 'merge_group') }}
+    if: ${{ github.actor != 'dependabot[bot]' && (!contains(github.event.pull_request.labels.*.name, 'Skip ARM') || github.event_name == 'push' || github.event_name == 'merge_group') }}
     runs-on: ubuntu-24.04
     needs: [arm-unittest-matrix]
     steps: