compose: Remove unnecessary 10x margin.
compose: Remove unnecessary 10x margin.

This margin was ignored and will become a liability with future
changes to the compose box HTML.

hackerkid/zulip,hackerkid/zulip,punchagan/zulip,hackerkid/zulip,zulip/zulip,kou/zulip,eeshangarg/zulip,eeshangarg/zulip,zulip/zulip,andersk/zulip,punchagan/zulip,zulip/zulip,eeshangarg/zulip,rht/zulip,rht/zulip,kou/zulip,kou/zulip,zulip/zulip,andersk/zulip,rht/zulip,zulip/zulip,hackerkid/zulip,andersk/zulip,andersk/zulip,andersk/zulip,kou/zulip,rht/zulip,hackerkid/zulip,punchagan/zulip,hackerkid/zulip,punchagan/zulip,rht/zulip,andersk/zulip,punchagan/zulip,zulip/zulip,punchagan/zulip,kou/zulip,hackerkid/zulip,kou/zulip,eeshangarg/zulip,rht/zulip,kou/zulip,eeshangarg/zulip,eeshangarg/zulip,eeshangarg/zulip,zulip/zulip,punchagan/zulip,andersk/zulip,rht/zulip