[CI] Increase stage-c-test-4-gpu-b200 partitions from 4 to 5 (#22395)

Co-authored-by: Alison Shao <alison.shao@MacBook-Pro-D2W773R9CD.local>

.github/workflows/pr-test.yml

@@ -1230,7 +1230,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        part: [0, 1, 2, 3]
+        part: [0, 1, 2, 3, 4]
 
     steps:
       - name: Checkout code
@@ -1261,7 +1261,7 @@ jobs:
           CONTINUE_ON_ERROR_FLAG: ${{ needs.check-changes.outputs.continue_on_error == 'true' && '--continue-on-error' || '' }}
         run: |
           cd test
-          python3 run_suite.py --hw cuda --suite stage-c-test-4-gpu-b200 --auto-partition-id ${{ matrix.part }} --auto-partition-size 4 --timeout-per-file 1800 $CONTINUE_ON_ERROR_FLAG
+          python3 run_suite.py --hw cuda --suite stage-c-test-4-gpu-b200 --auto-partition-id ${{ matrix.part }} --auto-partition-size 5 --timeout-per-file 1800 $CONTINUE_ON_ERROR_FLAG
 
       - uses: ./.github/actions/upload-cuda-coredumps
         if: failure()