loading and error enhancements in studio

[aditya-mitra]

Summary

Show a loading indicator beside the entity whose components are being loaded.
Also fix the error tooltip which was not properly showing the detailed errors.

Note: I replaced hasComponent(entity, myComponent) set/removeComponent with just set/removeComponent as both check for entity before setting/removing

References

closes part of #9201

QA Steps

3fe46b43-eda4-4db8-80cb-cf551d9dbb24.mp4

[AidanCaruso]

Looks really good, definitely improves the loading/error tips. However, I feel the need to point out that this is hampered a bit by the model component's error handling logic generally being wrong. Nonexistant models returning 404s seemingly aren't always caught if they are of a supported asset type, and invalid URLs get flagged as invalid asset types. This can be fixed in another PR down the line.