remove uneccesary fullscan Roi flag

The fullscan flag is not needed here - it is really an abuse of the Roi descriptor to use an Roi with different parameters where those parameters are used and still have it as a fullscan Roi.

This removes the fullscan flag, and just uses a standard RoiDescriptor. This will add around 1 ms to the SCT and Pixel RegionSelector calls, but should have otherwise no impact.

If saving that 1 ms in the FS tracking instance taking ~ 600 ms is seen to be important we can modify the SCT and Pixel data preparation to cache the full module list so that the RS doesn';t need to be called at all, and then this will save around 7 ms overall which would be a better solution.

This is only a temporary change however, since the affected code should be moved to the Roi creator, so this change is just to remove the unwanted method from the RoiDescriptor so that it isn't forgotten.