[web] reintroduce error message to thread settings modal

Summary:
This diff reintroduces the error message for the thread settings modal. Additionally, I deleted the SubmitSection component since this was no longer being used

Linear task: https://linear.app/comm/issue/ENG-5943/extendmodify-the-modal-props-api-to-follow-new-modal-designs

Depends on D11034

Test Plan:
Please see the screenshots below

Reviewers: atul, inka

Reviewed By: atul

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D11035