ci: use more cores for the extensions test (#2568)

This test is running into timing issues in our CI.

Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>

.github/workflows/test.yaml

@@ -54,7 +54,7 @@ jobs:
       - uses: ./.github/actions/teardown-localstack
   test-run-extensions:
     name: Run zot with extensions tests
-    runs-on: ubuntu-latest-4-cores
+    runs-on: ubuntu-latest-16-cores
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5