Implement migrator for removal of `sample_state_information` slot from `PortionOfSubstance` class

[eecavanna]

Background

In PR #2354, the sample_state_information slot is being removed from the PortionOfSubstance class.

In the schema docs, I can see that the PortionOfSubstance class is in the range of the substances_used slot of the following schema classes:

• Extraction
• StorageProcess
• DissolvingProcess
• ChemicalConversionProcess
• MobilePhaseSegment

Task

The task is to write a migrator that locates each "instance" of each of those classes in the database, checks whether it has a substances_used field and—if it does—deletes the sample_state_information field from each object in that substances_used field.

Add the migrator to that PR branch.