* [LYN-3717] When pulling in an actor FBX, two entities are spawned & [ATOM-15258] Clicking and Dragging fbx file into viewport produces 2 entities
* Added another operation to the CanSpawnEntityForProduct that checks the other products and can veto the creation process.
* The model product will not create an entity in case there is already an actor exported, which prevents the issue reported by two different teams/users.
* ensure brute force ray intersection works in the same space as kd-tree intersection
* add additional tests for ray casts against meshes using brute force approach
* update api and add some additional test cases
* comment tidy-up and other small updates/fixes for ray intersection code
* fix issue with values at the end of a ray
Steve Pham
Benjamin Jillich
Tom Hulton-Harrop
alexpete