Move the / to . replcement only for import_module call, error message was impacted

[preearor]

• It impacted the error message in case user handler name is a/module1.handler, and the module was not found it would raise error as a.module1 not found rather than a/module1 is not found. Corrected this behavior

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[carlzogh]

Let's also add a test to assert that such error messages contain the original handler notation too 😀