Visualization example with WCSAxes have extra ticks not supposed to be there

@eteq can fill in the details.

During WCSAxes example presentation, one person pointed out there are extra straight ticks with no dotted lines, in addition to the slanted ticks, which caused confusion. The example should be fixed so the straight ticks are hidden.

Locate the WCSAxes visualization example in the workshop materials and run or render it as presented. Inspect the resulting plot for the extra straight ticks without dotted lines; done means the example shows only the intended slanted ticks and no confusing extra tick marks.

Written by the indexing model from the issue text.