Allow Binning mode MEAN with ImageOpMode HardAndSoft

The current implementation requires ImageOpMode to be SoftOnly. Instead we should not use the hardware binning (even if available) when using the MEAN mode.

Feedback from BM18:

We had to deactivate the new option because the activation of the soft system means that the frame rate is calculated on the full frame instead of taking into account the vertical ROI. It is something that can be fine for the 2x optic and eventually the 1x optic as we typically take most of the vertical size of the picture, but it is not usable for all the lower resolution optics where we use much smaller vertical FOV and reduce the time per frame accordingly.

In other words, it is not currently possible to use the new binning mode with the hard ROI.