The message textarea blocks undo of the pasted text

[dca00]

Describe the bug Any normal HTML textarea undoes text paste. The textarea in this app does not.

To Reproduce Steps to reproduce the behavior:

1. Paste any text to the clipboard
2. Paste into a new message
3. Hit undo key combination
4. Undo does not occur

Expected behavior Undo should work the same as in any HTML textarea and clear the pasted text

Environment (please complete the following information):

• Desktop
• Browser Firefox]
• Converse.js version [e.g. 12.0.0]