stream settings: Fix scrollbar bug on unsubscribing themselves.
stream settings: Fix scrollbar bug on unsubscribing themselves.

Fix scrollbar not updating when user unsubscribe themselves
from "Stream members" list, by clicking "Unsubscribe" button.

Fixes #9029

jackrzhang/zulip,kou/zulip,shubhamdhama/zulip,tommyip/zulip,rht/zulip,zulip/zulip,zulip/zulip,eeshangarg/zulip,showell/zulip,andersk/zulip,hackerkid/zulip,kou/zulip,shubhamdhama/zulip,shubhamdhama/zulip,rishig/zulip,dhcrzf/zulip,rht/zulip,kou/zulip,eeshangarg/zulip,showell/zulip,dhcrzf/zulip,shubhamdhama/zulip,kou/zulip,hackerkid/zulip,timabbott/zulip,synicalsyntax/zulip,punchagan/zulip,kou/zulip,hackerkid/zulip,tommyip/zulip,tommyip/zulip,showell/zulip,synicalsyntax/zulip,punchagan/zulip,synicalsyntax/zulip,synicalsyntax/zulip,brainwane/zulip,punchagan/zulip,rishig/zulip,timabbott/zulip,hackerkid/zulip,eeshangarg/zulip,punchagan/zulip,showell/zulip,tommyip/zulip,hackerkid/zulip,shubhamdhama/zulip,punchagan/zulip,timabbott/zulip,synicalsyntax/zulip,showell/zulip,timabbott/zulip,zulip/zulip,andersk/zulip,eeshangarg/zulip,dhcrzf/zulip,eeshangarg/zulip,kou/zulip,eeshangarg/zulip,dhcrzf/zulip,kou/zulip,synicalsyntax/zulip,hackerkid/zulip,rishig/zulip,hackerkid/zulip,jackrzhang/zulip,rishig/zulip,eeshangarg/zulip,synicalsyntax/zulip,andersk/zulip,jackrzhang/zulip,brainwane/zulip,andersk/zulip,rishig/zulip,rht/zulip,dhcrzf/zulip,andersk/zulip,dhcrzf/zulip,andersk/zulip,brainwane/zulip,tommyip/zulip,rht/zulip,brainwane/zulip,showell/zulip,dhcrzf/zulip,jackrzhang/zulip,rht/zulip,rht/zulip,punchagan/zulip,punchagan/zulip,timabbott/zulip,rishig/zulip,rishig/zulip,shubhamdhama/zulip,brainwane/zulip,shubhamdhama/zulip,brainwane/zulip,tommyip/zulip,brainwane/zulip,jackrzhang/zulip,jackrzhang/zulip,timabbott/zulip,showell/zulip,tommyip/zulip,zulip/zulip,zulip/zulip,timabbott/zulip,andersk/zulip,jackrzhang/zulip,zulip/zulip,rht/zulip,zulip/zulip