Inconsistency in ScanImageTiffSinglePlaneImagingExtractor sampling frequency data for multi-channels and multi-planes imaging data

[alessandratrapani]

For multi-channel and multi-planes imaging data, the sampling frequency extracted is the one for the round-robin acquisition

roiextractors/src/roiextractors/extractors/tiffimagingextractors/scanimagetiffimagingextractor.py

Line 135 in 3f93d76

self._sampling_frequency = parsed_metadata["sampling_frequency"]

The sampling frequency for the volumetric imaging should be the sampling frequency of the single channel. ('SI.hRoiManager.scanVolumeRate' ScanImage metadata)
We could define an extra property: plane_rate_acquisition that would be equivalent to the round-robin acquisition rate

This solution stand on the assumption that all channels are acquired at the same time