stream_settings: Remove all_streams variable.
stream_settings: Remove all_streams variable.

We no longer need this global variable after the prior commit.

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