Delay for new hover service does not respect different origins

[colin-grant-work]

Original message:
@msujew, I notice that in Theia with this change, if any hover has recently been rendered, then any other hover, of the same or different kind, will be rendered immediately, but in VSCode, it appears to differ by source. So e.g. if you hover over an extension tree node, get the hover, then hover over a sidebar tabbar icon, the tabbar icon's title hover will appear immediately, but in VSCode, it will only hover after a delay.

Originally posted by @colin-grant-work in #11869 (comment)