do_update_embedded_data: Remove unnecessary `transaction.atomic`.
do_update_embedded_data: Remove unnecessary `transaction.atomic`.

There isn't any attachments code involved here.
This was added in c93f1d4eda71ddcca5ba05d0bf9fbfc8895829e2, probably accidentally.

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