Rework the parsing logic to be more resiliant against non-compliant html

[simlay]

This is a sibling issue to liveview-native/liveview-client-swiftui#1410.

Currently if parsing fails a ParseError is returned from core. It's still an error but similar to browsers the parsing should be resilient to erroneous elements.

This might involve modifying the liveview-native fork of htmlgum on the lvn branch.