compose: Prevent upload files tooltip from hiding behind left sidebar.
compose: Prevent upload files tooltip from hiding behind left sidebar.

Resolves the issue by appending tooltip to document body.

Fixes: #20639.

rht/zulip,kou/zulip,andersk/zulip,eeshangarg/zulip,rht/zulip,andersk/zulip,kou/zulip,eeshangarg/zulip,andersk/zulip,eeshangarg/zulip,eeshangarg/zulip,andersk/zulip,kou/zulip,andersk/zulip,andersk/zulip,rht/zulip,andersk/zulip,eeshangarg/zulip,zulip/zulip,zulip/zulip,eeshangarg/zulip,zulip/zulip,kou/zulip,rht/zulip,kou/zulip,rht/zulip,zulip/zulip,zulip/zulip,zulip/zulip,kou/zulip,rht/zulip,eeshangarg/zulip,rht/zulip,kou/zulip,zulip/zulip