api: Remove incorrect realm setting in 'realm/update_dict' schema.
api: Remove incorrect realm setting in 'realm/update_dict' schema.

We incorrectly include many realm settings in the data section of
'realm/update_dict' schema. It should only contain the settings
related to message edit, realm icon, realm logo and authentication
methods and not other settings, becausea all the other settings send
'realm/update' event and not 'realm/update_dict' event.

This commit only removes 'add_emoji_by_admins_only' and others will
be removed separately.

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