Handle undefined data in sampleSearch.
Handle undefined data in sampleSearch.

It's throwing an error between adding a column
and loading the data.

acthp/ucsc-xena-client,acthp/ucsc-xena-client,ucscXena/ucsc-xena-client,ucscXena/ucsc-xena-client,acthp/ucsc-xena-client,ucscXena/ucsc-xena-client,ucscXena/ucsc-xena-client,ucscXena/ucsc-xena-client