Camera auto-focus not working on macOS

[DavidMansolino]

Describe the Bug
The focus is not done on macOS:

[omichel]

On Windows, it is working properly.

[DavidMansolino]

On Ubuntu too.

[DavidMansolino]

The focus field is correctly changing from ~0.1 to ~0.6 as on Ubutnu, but there is no visible impact on the camera image.

[DavidMansolino]

I checked on R2020a-rev1 and this is not a regression.
It actually seems that the focus is somehow working, but the result is not as nice as on the other platforms, the non-blur part is way less visible.

[DavidMansolino]

Since this PR is not a regression and is probably due to the GPU and not a bug, I will postpone it so that we can keep going with the release.