Change test-pr workflow to always run on amd64

.gitea/workflows/test-pr.yaml

@@ -9,7 +9,7 @@ env:
 
 jobs:
   "Build Image":
-    runs-on: ubuntu-docker-latest
+    runs-on: [ubuntu-docker-latest, linux/amd64]
     steps:
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
@@ -32,7 +32,7 @@ jobs:
           username: Gitea
           avatarUrl: ${{ vars.RUNNER_ICON_URL }}
   "Notify":
-    runs-on: ubuntu-docker-latest
+    runs-on: [ubuntu-docker-latest, linux/amd64]
     needs: ["Build Image"]
     steps:
       - name: Notify of success