Call torchrec cpu tests from fbgemm test gha (#4424)

Summary:

This diff kicks off the torchrec cpu unittests along with fbgemm's cpu tests when there is a pull request on fbgemm

Differential Revision: D77598015

Author: nipung90

.github/workflows/fbgemm_gpu_ci_cpu.yml

@@ -200,3 +200,11 @@ jobs:
       env:
         PYPI_TOKEN: ${{ secrets.PYPI_TOKEN }}
       run: . $PRELUDE; publish_to_pypi $BUILD_ENV "$PYPI_TOKEN" *.whl
+
+
+  # Run torchrec CPU tests
+  torchrec_cpu_tests:
+    permissions:
+      id-token: write
+      contents: read
+    uses: pytorch/torchrec/.github/workflows/reusable_unittest_ci_cpu.yml@nipun/make_cpp_tests_reusable