[lib] Make selector types more consistent

Summary:
Use the types that are already defined.

https://linear.app/comm/issue/ENG-4813/migrate-getclientresponsesselector-to-a-spec

Depends on D9009

Test Plan: Flow

Reviewers: kamil, bartek, inka

Reviewed By: bartek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D9025