We currently log any unknown property access on the global (window). This has
proven pretty useful when debugging, often letting us know a type we're
completely missing.
However, it isn't just about what types we have, it's also about the properties
those types expose. Inspired by the wasted time spent on
https://github.com/lightpanda-io/browser/pull/1473, this commit adds the same
type of logging for unknown properties on objects. In debug mode only. This is
only done for objects which don't have their own NamedIndexer.