Update VE core submodule for cherry-picks to make math inspector work

Use new dm.Surface method for checking undo history state
(hasPastState -> hasBeenModified).

New changes:
38776df [BREAKING CHANGE] Refactor history state methods to better suit uses
0c5238c Add system to dm.Surface for staging changes
8f0077c Only hide popups on selection change
1ff6c8d Create ve#contains
92be9e2 Prevent pasteTarget selection while already selected
b3e5759 Make ve.dm.Surface#breakpoint not crash

Change-Id: I5437e837f0b66a3094a7c1c43c91fcdd17b10783