Also fixes behaviour where deprecated functions actually
no longer did what they used to do.
Refs #27736

This commit adds the normalisation drop down option without any functionality

Add this to the SliceViewer for MatrixWorkspaces

list.clear() isn't available on python 2, changed to del

The imshow limits were not updating when the colorbar changed, this forcefully set the limits on the data from the colorbar

Closes #25599

Also fixed #25603

Fixes #25619