Update sliceviewer testing docs

[RichardWaiteSTFC]

Issues found during manual testing for 6.10 #37338

1. As described in Sliceviewer-Zooming in outside the extent of the data does not change Log colorscale option #37369 using MatrixWorkspace

While following the testing instructions for sliceviewer at https://developer.mantidproject.org/Testing/SliceViewer/SliceViewer.html#id4
at step 5 when zooming in to a region outside the extent of the data, the log colorscale was still enabled as shown below. But the test instructions says otherwise.

The behaviour is OK, just update the docs with the expected behaviour.

2. As described in Sliceviewer-Zooming in outside the extent of the data does not change Log colorscale option #37369 using MatrixWorkspace

In addition, at step7 at https://developer.mantidproject.org/Testing/SliceViewer/SliceViewer.html#id4 when track cursor is unchecked, clicked on the sliceviewer and when axes are transposed, the values of the table are cleared and does not stay the same for the clicked position above. Is this as expected?

Yes the cursor info table will update next time the colrofill plot is clicked

3. As described in Sliceviewer-update in slicepoint does not update cursor info table #37371 with MD workspace

When following the sliceviewer test instructions as listed : https://developer.mantidproject.org/Testing/SliceViewer/SliceViewer.html#id5
at step 5, when the slicepoint is changed along one of the non-viewed axis, the slicepoint is not updated in the cursor info table

Yes the cursor info table will update next time the colrofill plot is clicked