The callers either set a default limit or manually handle a None-limit later on (by setting a default value). Update the callers to always instantiate PaginationConfig with a default limit and then assume the limit is non-None.
HomeServer.get_datastore()
The presence of this method was confusing, and mostly present for backwards compatibility. Let's get rid of it. Part of #11733
Applies the changes from #10665 to additional modules.
