8777 Cleanup hookstate usage around components

[DanielBelmes]

Summary

Changed removeComponent set to none as per hookstates api.
Removed EntityRemovedComponent system
Removed subscribable from existanceMapState

References

#8777

Explanation

🤖 Generated by Copilot at 347d53f

• Simplify entity removal logic by using bitECS.removeEntity and getAllEntities instead of a custom EntityRemovedComponent and query (link, link, link, link, link, link, link, link, link, link, link, link)
• Remove Subscribable generic parameter and subscribable() argument from existenceMapState property in Component interface and defineComponent function, as they are not needed (link, link, link)
• Use none instead of undefined to set the component state when removing a component, and add some commented out code for future implementation of destroying and deleting the state map entry (link)
• Add a comment explaining why a hookstate is needed for the stateMap entry even if the component is undefined in useOptionalComponent function (link)

Checklist

• If this PR is still a WIP, convert to a draft
• When this PR is ready, mark it as "Ready for review"
• ensure all checks pass
• Changes have been manually QA'd
• Changes reviewed by at least 2 approved reviewers

[speigg]

Build is failing, please run npm run check-errors

[HexaField]

we spoke, and the test can be improved