Remove remaining matrix shell condition

- Remove shell condition from Test Docker step
- All steps now use default bash shell for Linux-only matrix

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

Author: camille-004

.github/workflows/ci.yml

@@ -34,7 +34,6 @@ jobs:
 
     - name: Test Docker
       timeout-minutes: 5
-      shell: ${{ matrix.os == 'windows' && 'pwsh' || 'bash' }}
       run: |
         docker --version
         docker run --rm hello-world