Improve type check for reading attribute
Improve type check for reading attribute

This is more logical than the previous case, and should cover most
things we are interested in.

This actually fixes an error as well that was sometimes occurring
because sometimes the first item in the array was a string.

Signed-off-by: Patrick Avery <743342299f279e7a8c3ff5eb40671fce3e95f13a@kitware.com>

OpenChemistry/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz,OpenChemistry/tomviz