Trim PR ID property before checking for truthiness
Trim PR ID property before checking for truthiness

This helps guard against accidentally specifying whitespace-only values
on the command-line.

apache/beam,apache/beam,lukecwik/incubator-beam,lukecwik/incubator-beam,chamikaramj/beam,robertwb/incubator-beam,apache/beam,RyanSkraba/beam,robertwb/incubator-beam,robertwb/incubator-beam,charlesccychen/incubator-beam,RyanSkraba/beam,rangadi/beam,chamikaramj/beam,robertwb/incubator-beam,charlesccychen/beam,rangadi/beam,apache/beam,RyanSkraba/beam,lukecwik/incubator-beam,chamikaramj/beam,charlesccychen/beam,markflyhigh/incubator-beam,chamikaramj/beam,markflyhigh/incubator-beam,iemejia/incubator-beam,charlesccychen/beam,chamikaramj/beam,charlesccychen/beam,charlesccychen/beam,apache/beam,apache/beam,lukecwik/incubator-beam,charlesccychen/incubator-beam,markflyhigh/incubator-beam,chamikaramj/beam,markflyhigh/incubator-beam,rangadi/incubator-beam,robertwb/incubator-beam,rangadi/beam,markflyhigh/incubator-beam,rangadi/beam,rangadi/beam,rangadi/beam,robertwb/incubator-beam,charlesccychen/incubator-beam,lukecwik/incubator-beam,RyanSkraba/beam,rangadi/incubator-beam,iemejia/incubator-beam,rangadi/incubator-beam,lukecwik/incubator-beam,apache/beam,RyanSkraba/beam,chamikaramj/beam,robertwb/incubator-beam,apache/beam,lukecwik/incubator-beam,RyanSkraba/beam,apache/beam,lukecwik/incubator-beam,chamikaramj/beam,rangadi/beam,chamikaramj/beam,mxm/incubator-beam,mxm/incubator-beam,markflyhigh/incubator-beam,chamikaramj/beam,charlesccychen/beam,lukecwik/incubator-beam,lukecwik/incubator-beam,charlesccychen/beam,apache/beam,robertwb/incubator-beam,RyanSkraba/beam,robertwb/incubator-beam,markflyhigh/incubator-beam,robertwb/incubator-beam,apache/beam