websocket_client: Use get_system_bot.
websocket_client: Use get_system_bot.

This messy code is used only for our websocket Nagios tests, so using
get_system_bot makes sense.

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