[TEST] Run twister with test-runner-v2

Author: stephanosio

.github/workflows/twister-prep.yaml

@@ -17,7 +17,7 @@ jobs:
   prep_pr:
     if: github.repository_owner == 'zephyrproject-rtos' && github.event_name == 'pull_request_target'
     runs-on:
-      group: zephyr-runner-v2-linux-x64-4xlarge
+      group: test-runner-v2-linux-x64-4xlarge
     container:
       image: ghcr.io/zephyrproject-rtos/ci-repo-cache:v0.27.4.20241026
       options: '--entrypoint /bin/bash'