increase max sample number from 30K to 50K
increase max sample number from 30K to 50K

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