[native] Use DisconnectedBar logic from hook

Summary: Used newly introduced hooks in native app.

Test Plan: The change was teted on virtual iOS device with different network conditions. I didn't observed any behavior change.

Reviewers: palys-swm, atul, benschac, ashoat

Reviewed By: palys-swm, ashoat

Subscribers: ashoat, Adrian, karol-bisztyga

Differential Revision: https://phabricator.ashoat.com/D2849