[web] Store edited message draft in the state

Summary: Enabled user to make changes to the text. Storing the draft in the EditState.

Test Plan: Run the app. Checked if user can edit text in the input bar. Checked if the state is updated.

Reviewers: michal, inka

Reviewed By: michal

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D7825