Remove deprecated code from Djblets.
Review Request #12897 — Created March 17, 2023 and submitted — Latest diff uploaded
This change removes all deprecated code marked for removal in Djblets
4.0. The only complicated part of this is the ListEditWidget, which had
a "legacy" mode in which the widget handled separators and value
splitting. This wasn't used anywhere except unit tests.
Ran unit tests.