[web] Use hook instead of connect function in ThreadPicker

Summary: I also made the ThreadPickerOption just a hook instead since it seems to be fairly simple

Test Plan: Checked if you could still click on created threads and that features such as delete still worked

Reviewers: palys-swm, ashoat, atul

Reviewed By: ashoat

Subscribers: ashoat, KatPo, zrebcu411, Adrian, atul

Differential Revision: https://phabricator.ashoat.com/D825