Expose buildHitCorners function in ElementInput  (#4853)
Expose buildHitCorners function in ElementInput  (#4853)

* Made some functions static

* Changed to vec3 parameter

* Added comment on functions used by the Editor

Co-authored-by: Steven Yau <c4e01c0f87a9d4bf034f0f681553ace272d52b0f@snapchat.com>
playcanvas/engine,playcanvas/engine