message_edit: Fix unused parameter in most tests.
message_edit: Fix unused parameter in most tests.

The message ID is encoded in the URL, not the PATCH parameters, so
this argument was ignored.  I verified that it appears to have always
matched the value present in the URL.

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