Simplify usage of EntityWorldMut::move_entity_from_remove by making it a proper method

[JaySpruce]

Objective

Fixes #17345

The "probably more safety stuff" was probably referring to the EntityLocation needing to be valid for the given Entity or something like that, but that's not necessary if we just give it the actual EntityWorldMut.

Solution

• Added &mut self to move_entity_from_remove parameters.
• Removed most of the method's other parameters and replaced them with local variables derived from self.
• The method now directly updates the location field of the EntityWorldMut, which wasn't necessarily the case before.
  • EntityWorldMut::take passed in a mutable reference to the field, so it already worked like that.
  • EntityWorldMut::remove_bundle passed in a mutable reference to a local variable, which it then returned so that its caller could use it to update the location field. This seems unnecessarily convoluted.
• EntityWorldMut::remove_bundle no longer returns the entity's location, as it is now updated internally.
• Updated safety notes.
• Added unsafe blocks to some calls that had a safety note with no block.