Fix runner targeting to use RTX Pro 6000 GPU runner

- Change runs-on from ubuntu-latest to linux-amd64-gpu-rtxpro6000-latest-1
- Re-enable branch trigger for cd/initial-ci to test GPU runner
- Should now run on the correct GPU-enabled self-hosted runner

Signed-off-by: cdunning <cdunning@nvidia.com>

Author: camille-004

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ on:
 jobs:
   test:
     name: Test Environment
-    runs-on: ubuntu-latest
+    runs-on: linux-amd64-gpu-rtxpro6000-latest-1
 
     steps:
     - name: Checkout