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 queried string is, so when you have both property types, it is enough for the query to be found in one of them.