[no-relnote] Switch to public runners

Since we now use pr-copy-bot, we are not running image builds
from forks and as such the required secrets for pushing to the
ghcr are present.

Signed-off-by: Evan Lezar <elezar@nvidia.com>

.github/workflows/e2e.yaml

@@ -36,7 +36,7 @@ on:
 
 jobs:
   e2e-tests:
-    runs-on: linux-amd64-cpu4
+    runs-on: ubuntu-latest
     steps:
       - name: Check out code
         uses: actions/checkout@v4