Check marker has been set in SolARFiducialMarkerPoseEstimator::estimate()

[jim-bcom]

As suggested in this comment SolarFramework/Sample-Mapping#6 (comment)

We may want to check whether m_fiducialMarker has been set before doing anything in SolARFiducialMarkerPoseEstimator::estimate().

SolARModuleTools/src/SolARFiducialMarkerPoseEstimator.cpp

Line 86 in d17e379

FrameworkReturnCode SolARFiducialMarkerPoseEstimator::estimate(const SRef<Image> image, Transform3Df & pose)