Fix/workaround iframe parent

[salomita]

This is a workaround to avoid the replayer crashing when there's an error when trying to attach a #document to a non-iframe.

The replayer has a bug in which all the recording looks blank. This has been reported a couple of times: https://github.com/rrweb-io/rrweb/issues/1414 https://github.com/rrweb-io/rrweb/issues/1619

It is happening because the replayer is trying to appendChild(#document) onto a non-iframe. The workaround prevents it from doing it and prevents the replay from going blank. Still, this is a workaround and further investigation is needed to check if the event is corrupted or if there's a mismatch in the order