[lib] Create common logic for filtering available thread members actions

Summary:
Moved logic responsible for filtering menu items in thread members panel into shared function between mobile and web.
No logic changes has been made in the shared function itself.

Test Plan: In web app, action menu in members modal contains the same elements as before. In mobile app, in thread settings, the same members options are avaliable.

Reviewers: palys-swm

Reviewed By: palys-swm

Subscribers: ashoat, Adrian, atul, karol-bisztyga, benschac

Differential Revision: https://phabricator.ashoat.com/D3490