Object keyword search REST API only works on objects with both short and long string properties

Steps to reproduce:

1. Add an object of class AppWithinMinutes.String to a page
2. Set the short text property in it to a unique string like "Noos5uyu"
3. Open /xwiki/rest/wikis/xwiki/search?q=Noos5uyu&scope=objects

Expected result:

The page is listed.

Actual result:

The object isn't listed.

When using TourCode.TourClass and setting any string property it works as expected. This is because the implementation uses an inner join with both a short and a large string property on the same object ID and thus only matches objects that have both a short and a large string property. For the match itself, it doesn't matter where the query is.