ci: stop using the non-free 4-core runners (#2695)

Signed-off-by: Jeffrey Sica <me@jeefy.dev>
Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>
Co-authored-by: Jeffrey Sica <me@jeefy.dev>

.github/workflows/test.yaml

@@ -14,7 +14,7 @@ permissions: read-all
 jobs:
   test-run-minimal:
     name: Running zot without extensions tests
-    runs-on: ubuntu-latest-4-cores
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - name: Install go
@@ -93,7 +93,7 @@ jobs:
       - uses: ./.github/actions/teardown-localstack
   test-run-devmode:
     name: Running privileged tests on Linux
-    runs-on: ubuntu-latest-4-cores
+    runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5