Fix camera flipping on framebuffers between push/pop calls

[davepagurek]

Resolves #6470

Changes

• Makes sure yScale is copied in copy() and set()

Screenshots of the change

With the test sketch from the issue:

let fbo
function setup() {
  createCanvas(400, 400, WEBGL)
  fbo = createFramebuffer()
}

function draw() {
  fbo.begin()
  background(100)
  push()
  ortho(-width/2, width/2, -height/2, height/2, 0.1, 2000)
  translate(0, -100)
  box()
  pop()
  fbo.end()
  
  imageMode(CENTER)
  image(fbo, 0, 0)
}

Before:

After:

Live: https://editor.p5js.org/davepagurek/sketches/g32vQiLIO

PR Checklist

• npm run lint passes
• [Inline documentation] is included / updated
• [Unit tests] are included / updated