This PR fixes a bug where frames with children that have identical
dimensions would not be able to export as images.
When calculating masked page bounds, identical shapes would produce a
zero width/height masked page bounds.
### Change Type
- [x] `patch` — Bug fix
### Test Plan
1. Create a frame.
2. Create an image that is a child of the frame and the exact dimensions
of the frame (possibly using the console)
3. Export the image
### Release Notes
- Fix bug with getmaskedpagebounds calculation for identical parent /
child sizes
3c768867f2