DSO selector modals show results by relevance even if no query is given

[ybnd]

Describe the bug
Results shown in Community/Collection/Item selection modals are ordered by relevance.
When no query is given, this can be confusing and doesn't match up with the behaviour of the Collection selector in legacy DSpace.

To Reproduce
Steps to reproduce the behavior:

1. Log in to any DSpace instance as an admin
2. Open any DSO selector modal (e.g. new Item, edit Collection, ...)
   • The order of the results will be arbitrary

Expected behavior
For clarity, results should be ordered alphabetically by title when no query is given
This is mostly important for Communities and Collections

• Since there are fewer entries, the user is likely to expect them to match the "Top Communities" or "Community List" view
• Sort by relevance feels random

Related work
#1331

[ybnd]

@tdonohue this has significant overlap with the WIP #2011; @KoenP can address it within that PR if that's ok with you

[ybnd]

Closing, issue was already covered in
DSpace/DSpace#8404
#2007