Release exporter need to match Histology item based on partition date

[Nicklas Nordborg]

If a specimen has been partitioned twice with two Lysate and two Histology items there can be two stained items marked with the GoodStain annotation (one for each Histology). This causes the release exporter to fail:

More than one child sample with GoodStain=TRUE was found for specimen 'xxxxx'. 
This wizard can't be used until that is corrected.

The release exporter need to be update to choose the Histology item that was partitioned at the same time as the current Lysate item (since we are moving up from a raw bioassay we always have a lysate item).

Note that there may also be use cases where a second partition only created a new Lysate item and not any Histology. In this case, the original Histology item should be selected even if the partition dates are different.

In other words, the release exporter should always choose the Histology item having a partition date closest to the partition date of the Lysate item.

[Nicklas Nordborg]

(In [4586]) Fixes #999: Release exporter need to match Histology item based on partition date

This should be fixed now. The release exporter will always load the histology item first. If more than one is found it selects the one with a partition date closest to the partition date on the lysate. A missing date is an error condition.

Once the histology item is found, loading the GoodStain sample is more or less the same as before. Only one should exist and if more than one is found results in an error.