Undo/redo broken after using editor actions

[bugzilla-to-github]

This issue was created automatically by a script.

Bug 1687447

Bug Reporter: @julen CC: @mathjazz

Whenever users leverage any feature that programmatically adds/replaces text in the editor textarea fields, the native undo/redo function ceases to work. Besides not being practical, this can also lead to data loss, because inputted translations can be mistakenly overwritten without any way to get back to previous contents.