Small refactor in the way VertexBuffer for post effects is created. (#4700)
Small refactor in the way VertexBuffer for post effects is created. (#4700)

* Small refactor in the way VertexBuffer for post effects is created.

* even better

Co-authored-by: Martin Valigursky <2113fa600d719248203230de1894fe2542067d96@snapchat.com>
playcanvas/engine,playcanvas/engine