FS-9683: Pass call recovery status to Verto

Previously, users implementing a Verto workflow where both user login and
placing a new call are automated (eg., visiting a URL, and the videoconference
loads automatically) faced the challenge of not having a reliable way to know
that a page load will result in Verto's call recovery mechanism reconnecting
an existing detached call or not.

This adds a verto.clientReady JSON-RPC message, emitted after all calls are
re-attached, which contains a 'reattached_sessions' array, containing the
sess_id of any reattached session.

Client side, this can be caught in the onMessage handler, under the
$.verto.enum.message.clientReady key.

html5/verto/js/src/jquery.verto.js

@@ -606,6 +606,11 @@
 
                 break;
 
+            case 'verto.clientReady':
+                verto.callbacks.onMessage(verto, null, $.verto.enum.message.clientReady, data.params);
+                console.debug("CLIENT READY", data.params);
+                break;
+
             default:
                 console.error("INVALID METHOD OR NON-EXISTANT CALL REFERENCE IGNORED", data.method);
                 break;
@@ -2686,7 +2691,7 @@
 
     $.verto.enum.state = $.verto.ENUM("new requesting trying recovering ringing answering early active held hangup destroy purge");
     $.verto.enum.direction = $.verto.ENUM("inbound outbound");
-    $.verto.enum.message = $.verto.ENUM("display info pvtEvent");
+    $.verto.enum.message = $.verto.ENUM("display info pvtEvent clientReady");
 
     $.verto.enum = Object.freeze($.verto.enum);