Remove double `;` from NSW primary numbers `.xml` file to avoid error in ExpressionEvaluator

Hi,

this is a fix of the NSW detector description .xml file to avoid an error when the xml ExpressionEvaluator is parsing the file during the layout creation. Thanks to @dellacqu I could easily find the 3 occurences of a doube ;; which cause the ExpressionEvaluator to fail. With this fix, we ensure that the affected code blocks in xml are correctly parsed and interpreted.

Adding @rosati, @wleight and @cchau for muon software

Adding also @sroe who might be interested in this