Home/End don't work in contenteditable divs underneath FocusZone

[stuartlong]

Bug Report

Home/End keys don't work correctly when the user is inside of a contenteditable div inside of a FocusZone.

Steps

1. Place a contenteditable="true" div as the content for a Chat
2. Place your cursor in the div
3. Hit end key

Expected Result

The cursor goes to the end of the content editable text

Actual Result

The user is navigated to the last chat in the list

Version

0.34.0

Testcase

Unable to generate a test case due to #1607