Add mixed precision tests to ci_gpu

Summary: Mixed precision tests need gpu

Differential Revision: D76459337

Author: iden-kalemaj

.github/workflows/ci_gpu.yml

@@ -94,6 +94,17 @@ jobs:
           name: cifar10-gpu-reports
           path: runs/cifar10/test-reports
 
+      - name: Run mixed precision tests (CUDA)
+        run: |
+          mkdir -p runs/mixed_precision/test-reports
+          python -m unittest opacus.tests.mixed_precision_test
+
+      - name: Store mixed precision test results
+        uses: actions/upload-artifact@v4
+        with:
+          name: mixed-precision-gpu-reports
+          path: runs/mixed_precision/test-reports
+
       # To save resouces, there is no need to run all the tests.
       # - name: Run IMDb integration test (CUDA)
       #   run: |