Pager not working with AJAX-loaded child term list?

Problem/Motivation

It seems like the pager isn't working when loading the child items in the tree?

Steps to reproduce

Have a vocabulary with a term tree like this:

• iptc
  • keywords
    • goat
    • cow
    • cat
    • ... a few hundred more...

Load the Taxonomy Manager with default settings.
In the TM settings set Pager count to 25.

Open the TM page for this vocabulary.

Expand the "iptc" item, then "keywords".

Expected results:
* 25 items are loaded, then a pager is shown to load more.

Actual results:
* The entire tree is loaded.

Proposed resolution

Update the term loading logic so that the AJAX-loaded term list adheres to the "Pager count" setting.

Remaining tasks

Update the term loading logic so that the AJAX-loaded term list adheres to the "Pager count" setting.
Update test coverage.

User interface changes

Using the AJAX loader to load child terms only loads $pager_count terms at a time.

API changes

TBD

Data model changes

n/a