Fix display of changed avatars in old messages (page_params).

Our client code will now receive avatar_url in
page_params.people_list during page load, so it will be
able to use more current urls for old messages (the client
already had some logic for that and was just missing the
data).

We also add avatar_url to the realm_user/add event.

When we change the avatar, we make sure to always send a
realm_user/update event (even for bots).

We also needed to add avatar_version and
avatar_source to our active users cache.

zerver/lib/actions.py

@@ -356,6 +356,7 @@ def notify_created_user(user_profile):
                              user_id=user_profile.id,
                              is_admin=user_profile.is_realm_admin,
                              full_name=user_profile.full_name,
+                             avatar_url=avatar_url(user_profile),
                              is_bot=user_profile.is_bot))
     send_event(event, active_user_ids(user_profile.realm))
 
@@ -1915,17 +1916,17 @@ def do_change_avatar_fields(user_profile, avatar_source, log=True):
                                  avatar_url=avatar_url(user_profile),
                                  )),
                    bot_owner_userids(user_profile))
-    else:
-        payload = dict(
-            email=user_profile.email,
-            avatar_url=avatar_url(user_profile),
-            user_id=user_profile.id
-        )
 
-        send_event(dict(type='realm_user',
-                        op='update',
-                        person=payload),
-                   active_user_ids(user_profile.realm))
+    payload = dict(
+        email=user_profile.email,
+        avatar_url=avatar_url(user_profile),
+        user_id=user_profile.id
+    )
+
+    send_event(dict(type='realm_user',
+                    op='update',
+                    person=payload),
+               active_user_ids(user_profile.realm))
 
 def _default_stream_permision_check(user_profile, stream):
     # type: (UserProfile, Optional[Stream]) -> None