Unable to subtract workspaces

[MialLewis]

Describe the bug
During beta, the tester was unable to subtract two workspaces that should be subtractable. In this instance, the x bins did not match between the workspaces.

This is not a regression from 6.7.0, but we should look into why this is the case:
Datasets:
MAR29790 - Sample.
MAR29793 - Aluminium can.
MAR29794 - Aluminium can (alternate temperature).

Expected behavior
User expected to be able to subtract 93 datasets from 90 dataset.