As a system, when importing an execution results report that doesn't have tests executed, it should not return HTTP status code 500

When importing Execution results, if one of the reports generated doesn't contain any test executed, the endpoint returns HTTP Status:"500 Internal Server Error".
In that case, the report should be ignored, and if possible the message returned should warn about the report without execution results.

Steps to reproduce

Step	Result
Report used
Using the Xray Rest API to import the report