Make 'group-pm-with' more error-resistant.
Make 'group-pm-with' more error-resistant.

Previously, if the operand was an invalid email, the site would
throw a scary-looking browser error. Now, it has the same behavior
as other search exeptions, and simply returns no messages found.

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