Broken rules:

If possible, should make sure we only have one build target for Excel_Toolkit, which should be netstandard 2.0, and use for all builds. If works, should also remove additional ZCT build.

Whilst investigating this, it seems this means that the issue with saving larger files found and fixed by @pawelbaran in BHoM/Excel_UI#330 is no longer an issue, and the code and dependencies added to remedy the issue can be removed.

Suggestions to restore compliance:

Change target framework and align.