help: Fix left sidebar content in smaller window.
help: Fix left sidebar content in smaller window.

This fixes an issue where some of the content of left
sidebar gets visible even in smaller window which looks ugly.

Fixes: #10898.

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