[tracing] Do not wrap when tracing is not enabled

[kira-lin]

Why are these changes needed?

When using cross language call, because defined remote functions are wrapped by tracing helper, the module_name in function_descriptor will become tracing_helper, and thus fail to import.

Related issue number

Closes #16606

Checks

• I've run scripts/format.sh to lint the changes in this PR.
• I've included any doc changes needed for https://docs.ray.io/en/master/.
• I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

[kira-lin]

Hi @simon-mo could you please take a look?

[kira-lin]

The PR now pass test_tracing. The other test failures seems not related