Update VE core submodule to master (f340daa)

New changes:
4572291 Truncate undo stack before applying staged changes
79e7876 Move DesktopContext.css into desktop module
0c6f68c Localisation updates from https://translatewiki.net.
366774d Localisation updates from https://translatewiki.net.
f756c91 Localisation updates from https://translatewiki.net.

Change-Id: I255e628fc48461b636ae8767b5212910caf48365
Merge "Update VE core submodule to master (f340daa)"