Rich Text: Unnecessarily dispatching change actions

[aduth]

Issue Overview

The RichText component dispatches more change actions than necessary.

Steps to Reproduce

1. Create a post with a single paragraph and save it
2. Refresh the page and open Redux DevTools
3. Select the first paragraph and type a single letter
4. Deselect the block by clicking the title

Expected Behavior

A single change action is dispatched.

Current Behavior

Three change actions are dispatched:

• Two at the keypress
• One at the deselect

This wouldn't be entirely problematic if the value weren't a new array each time, as the reducer considers it a new value and updates references accordingly (thus triggering rerenders).

Possible Solution

Should we be checking that content has changed from RichText before triggering an update?

Related

Possibly related to #4956

cc @iseulde @youknowriad