RN: Design improvements for the mobile post draft area

Description

1. Especially on dark themes, should we make the draft area the same color as the center channel background (similar to how it looks on light themes)?
2. Should we consider updating the placement/sizing/style of the send icon?
3. Should we consider updating the placement/sizing/style of the attachment icon? Should we break up that menu into separate icons (ie Slack).
4. What about an expand collapse button if writing a long post.

Recommend some competitor research on what is common in other apps.

QA Test Steps

None

Status

Mana

4

Assignee

Eric Sethna

Reporter

Eric Sethna

Epic Link

None

Fix versions

Mattermost Team

UX

Sprint

Labels

None

GitHub Issue

None