Allow 'Show parent issue in hierarchy' scripted field to search empty values in JQL

As a Jira User

I want the 'Show parent issue in hierarchy' scripted field to be able to search empty values in JQL. Right now, the following will appear when trying to use it:

So that we can find Issues that are configured with the scripted field but do not return any values

Workaround:
Might be possible to achieve a similar requirement by using the ScriptRunner's JQL Functions e.g.: hasLinkType(), hasLinks(), linkedIssuesOf(), linkedIssuesOfAll()