Copying entities will also add clipboard data

[Maksims]

Partly fixes https://github.com/playcanvas/editor/issues/1369

When copying entities from hierarchy, will now add clipboard data, so it can be pasted in inspector attributes. Very useful when need to set multiple entities from hierarchy onto attribute entity array field.

https://github.com/user-attachments/assets/951d30dc-122a-49e7-b6cf-cf40a9cc9fa2