Bugfix. Only remove modals when disconnected

not while tearing down, otherwise the modals get removed while
reconnecting and we have stale references to modals no longer in the
DOM.

src/converse-modal.js

@@ -144,11 +144,8 @@ converse.plugins.add('converse-modal', {
 
 
         /************************ BEGIN Event Listeners ************************/
-        _converse.api.listen.on('afterTearDown', () => {
-            if (!_converse.chatboxviews) {
-                return;
-            }
-            const container = _converse.chatboxviews.el.querySelector("#converse-modals");
+        _converse.api.listen.on('disconnect', () => {
+            const container = document.querySelector("#converse-modals");
             if (container) {
                 container.innerHTML = '';
             }

src/headless/converse-chat.js

@@ -1239,7 +1239,7 @@ converse.plugins.add('converse-chat', {
 
         /************************ BEGIN Event Handlers ************************/
         _converse.api.listen.on('chatBoxesFetched', autoJoinChats);
-        _converse.api.listen.on('presencesInitialized', () => registerMessageHandlers());
+        _converse.api.listen.on('presencesInitialized', registerMessageHandlers);
 
         _converse.api.listen.on('clearSession', () => {
             if (_converse.shouldClearCache()) {