[FIX] mail: improve performance of ringing thread

Avoid iterating over all channels every time a new channel is added.

Part of task-2702450

closes odoo/odoo#81051

X-original-commit: 5359a8c354b0a6106d462fe8f047de946614b7b1
Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

addons/mail/static/src/models/messaging/messaging.js

@@ -356,10 +356,11 @@ registerModel({
          */
         publicPartners: many2many('mail.partner'),
         /**
-         * Threads for which the current partner has a pending invitation
+         * Threads for which the current partner has a pending invitation.
+         * It is computed from the inverse relation for performance reasons.
          */
-        ringingThreads: many2many('mail.thread', {
-            compute: '_computeRingingThreads',
+        ringingThreads: one2many('mail.thread', {
+            inverse: 'messagingAsRingingThread',
         }),
         rtc: one2one('mail.rtc', {
             default: insertAndReplace(),

addons/mail/static/src/models/thread/thread.js

@@ -1536,6 +1536,16 @@ registerModel({
                 return total + 1;
             }, baseCounter);
         },
+        /**
+         * @private
+         * @returns {FieldCommand}
+         */
+        _computeMessagingAsRingingThread() {
+            if (this.rtcInvitingSession) {
+                return replace(this.messaging);
+            }
+            return clear();
+        },
         /**
          * @private
          * @returns {mail.message[]}
@@ -2162,6 +2172,11 @@ registerModel({
             inverse: 'thread',
             isCausal: true,
         }),
+        messagingAsRingingThread: many2one('mail.messaging', {
+            compute: '_computeMessagingAsRingingThread',
+            inverse: 'ringingThreads',
+            readonly: true,
+        }),
         model: attr({
             readonly: true,
             required: true,