Enable issue link from issues to tests wrong way round

Hi SuWain 

Hope you are well. 

The only issue linking in Zephyr is via traceability Matrix. 

https://support.smartbear.com/zephyr-squad-cloud/docs/track-progress/traceability-matrix/new.html?sbsearch=relationship

This links issue types like stories/epics to testcases to cycles and then to defects etc 

In terms of creating composite relationships between issue types this is configured in Jira more so than Zephyr Squad. 

https://confluence.atlassian.com/adminjiraserver/configuring-issue-linking-938847862.html

https://community.atlassian.com/t5/Jira-questions/quot-tested-by-quot-isn-t-appears-in-the-links-options/qaq-p/1322506

Hope this helps

Vincent