[IMP] mail: remove useless guard 'Thread/hasComposerThreadTyping'

Thread/hasComposerThreadTyping is always set to boolean, so never `undefined`.

Task-2793280

closes odoo/odoo#86965

Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>

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

@@ -612,7 +612,7 @@ registerModel({
          * @returns {boolean|FieldCommand}
          */
         _computeHasThreadTyping() {
-            if (this.threadView && this.threadView.hasComposerThreadTyping !== undefined) {
+            if (this.threadView) {
                 return this.threadView.hasComposerThreadTyping;
             }
             return clear();