PostHog now filters browser notices after completed events

Our weekly error report told us all 243 browser notices needed attention. The page looked for a PostHog field before PostHog added it, so the filter could never match. We moved the check to the completed event. PostHog now adds the field, checks it, and sends only notices that pass. #dev

<caption>The page checked too early for a field that arrived later, so it now checks after the event is complete.</caption>