At once a second, it regularly skips whole seconds (because scheduler
isn't guaranteed to run exactly as often as specified). 10 updates a
second seems amicable and less noticeable to my eye.
Legacy skins should now always show the legacy hud components. The
conditional here is no longer valid as fallback lookups happen at a
*skin*-fallback level rather than internal *source*-fallback.
Put another way, `LegacyDefaultSkin` (with user customisations) should
still display the classic HUD components even if a font is not provided,
as that font will be available via the skin lookup hierarchy.
The TODO removed in this commit has been already resolved so this code
is no longer required.