Need way to bypass waitAssets selectively

[Jamie5]

waitAssets is of course quite useful, but there are times you want to allow some requests to still be waiting - for example, to test a loading state (with the play function) you want to open a page, but not let a request complete (so that the loading state stays visible). And if that request happens to be a GET, then ResourceWatcher will stay stuck on it. (Note that requests are mocked out with msw, though I don't think that's necessarily relevant here)