This commit fixes the "Expected null to equal '401R'" errors that
surfaced after the Puppeteer 18 upgrade. Note that even before that
this would have been an improvement because it takes some time between
scripting being reported ready (i.e., triggering the execution of any
OpenActions) and those OpenActions actually completing execution, so
it's only safe to check which element is focused if we know an element
actually became focused.
606fb8c394