Some code disables the dropdown behaviour when ULS is loaded, however
it does not always appear to be working as the `ext.uls.interface`
module may be loaded for other things unrelated to the compact
languages link button.
The safest thing to do for now seems to be to check the configuration
flag wgULSisCompactLinksEnabled. In future, perhaps a hook event could
be added to ULS and that could be subscribed to instead.
Bug: T287191
Change-Id: I0cf8d387919078aabc9e77a0a452f8b3364016ee
jdlrobson
bwang