Remove optimize event slices checkbox from ISIS SANS GUI

[rbauststfc]

See #37836 for the context of this work.

This issue is to cover the short-term step of removing the Optimize event slices checkbox on the Settings->General, Scale, Event Slice, Sample tab of the ISIS SANS GUI. The checkbox should be removed from the interface only. The underlying supporting code should not yet be removed. The workflow should run as if the checkbox had not been selected by the user.