DEV: Refactor basic-topic-list to use topic-list-item on mobile (PR #10105)

Previously, basic-topic-list had its own implementation of topic-list-item on mobile, which made it more difficult to maintain and extend. The visible difference was that the basic-topic-list implementation had no large avatar on the left. This commit adds a new hideMobileAvatar parameter to topic-list-item and topic-list, and sets it to true for the basic-topic-list component.


How safe is this to merge 2 days before a release though? Maybe it should wait.

Yes it should definitely wait :+1: