node tests: Remove unreachable match case.
node tests: Remove unreachable match case.

Since util.extract_pm_recipients() won't return a recipient if it's only
composed by whitespaces, considering such recipient in the matcher is
unnecessary.

vaidap/zulip,brockwhittaker/zulip,mahim97/zulip,kou/zulip,jackrzhang/zulip,rht/zulip,tommyip/zulip,eeshangarg/zulip,vabs22/zulip,brainwane/zulip,tommyip/zulip,timabbott/zulip,amanharitsh123/zulip,shubhamdhama/zulip,shubhamdhama/zulip,dhcrzf/zulip,vaidap/zulip,brainwane/zulip,rishig/zulip,vabs22/zulip,brockwhittaker/zulip,brockwhittaker/zulip,rht/zulip,zulip/zulip,synicalsyntax/zulip,hackerkid/zulip,mahim97/zulip,verma-varsha/zulip,Galexrt/zulip,showell/zulip,jrowan/zulip,hackerkid/zulip,eeshangarg/zulip,Galexrt/zulip,timabbott/zulip,vaidap/zulip,synicalsyntax/zulip,kou/zulip,zulip/zulip,synicalsyntax/zulip,amanharitsh123/zulip,brainwane/zulip,andersk/zulip,hackerkid/zulip,punchagan/zulip,mahim97/zulip,jackrzhang/zulip,brainwane/zulip,andersk/zulip,zulip/zulip,Galexrt/zulip,rht/zulip,rishig/zulip,eeshangarg/zulip,Galexrt/zulip,dhcrzf/zulip,dhcrzf/zulip,jrowan/zulip,rishig/zulip,timabbott/zulip,dhcrzf/zulip,vaidap/zulip,brockwhittaker/zulip,brainwane/zulip,vaidap/zulip,timabbott/zulip,verma-varsha/zulip,shubhamdhama/zulip,vaidap/zulip,mahim97/zulip,vabs22/zulip,timabbott/zulip,dhcrzf/zulip,kou/zulip,verma-varsha/zulip,eeshangarg/zulip,jackrzhang/zulip,verma-varsha/zulip,zulip/zulip,brockwhittaker/zulip,dhcrzf/zulip,tommyip/zulip,rishig/zulip,andersk/zulip,Galexrt/zulip,kou/zulip,punchagan/zulip,jrowan/zulip,rht/zulip,tommyip/zulip,shubhamdhama/zulip,andersk/zulip,kou/zulip,zulip/zulip,shubhamdhama/zulip,eeshangarg/zulip,punchagan/zulip,amanharitsh123/zulip,jrowan/zulip,vabs22/zulip,brockwhittaker/zulip,eeshangarg/zulip,rht/zulip,vabs22/zulip,jackrzhang/zulip,punchagan/zulip,showell/zulip,showell/zulip,tommyip/zulip,rishig/zulip,amanharitsh123/zulip,punchagan/zulip,Galexrt/zulip,andersk/zulip,rishig/zulip,rishig/zulip,showell/zulip,showell/zulip,zulip/zulip,synicalsyntax/zulip,brainwane/zulip,synicalsyntax/zulip,shubhamdhama/zulip,punchagan/zulip,jackrzhang/zulip,dhcrzf/zulip,amanharitsh123/zulip,hackerkid/zulip,synicalsyntax/zulip,synicalsyntax/zulip,brainwane/zulip,zulip/zulip,jackrzhang/zulip,amanharitsh123/zulip,jrowan/zulip,showell/zulip,vabs22/zulip,showell/zulip,jackrzhang/zulip,kou/zulip,hackerkid/zulip,verma-varsha/zulip,Galexrt/zulip,punchagan/zulip,timabbott/zulip,tommyip/zulip,rht/zulip,timabbott/zulip,eeshangarg/zulip,hackerkid/zulip,shubhamdhama/zulip,jrowan/zulip,andersk/zulip,rht/zulip,kou/zulip,mahim97/zulip,mahim97/zulip,andersk/zulip,hackerkid/zulip,verma-varsha/zulip,tommyip/zulip