Updating the tree component to only use a different icon for when a node does not have children and put the emptytext as the title on that instead of a row displaying No Children. Also fixing a bug where updating the light DOM was not updating the showEmptyIcon property.
Updating the tree component to only use a different icon
for when a node does not have children and put the emptytext
as the title on that instead of a row displaying No Children.
Also fixing a bug where updating the light DOM was not updating
the showEmptyIcon property.

Change-Id: I8b182ea7caa4a144444d27914fe8edcfaee06c0d

vanadium/browser,vanadium/browser,vanadium/browser,vanadium/browser