[FIX] mail: prevents video access traceback after ending a call

Before this commit, it was assumed that the call was still active when
the video permission was granted, this assumption was false and this
commit fixes this issue.

closes odoo/odoo#75999

Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

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

@@ -795,6 +795,9 @@ function factory(dependencies) {
                 const sendDisplay = force !== undefined ? force : !this.sendDisplay;
                 await this._updateLocalVideoTrack(type, sendDisplay);
             }
+            if (!this.currentRtcSession) {
+                return;
+            }
             if (!this.videoTrack) {
                 this.currentRtcSession.removeVideo();
             } else {