After ending the notification playback, we set the ".src" property to null, which immediately stop the internal player of mobile browser (tested on Chrome for Android - device list is on #11458).
For the specific list of devices, this prevents the internal buffer error "-61" described in #11458.
Fixes#11458.
If activity check was enabled in server, the activity check modal wasn't showed
to users and after a given time the user was disconnect, also fix the meeting-end
and error-screen messages, informing the user the reason why he was kicked.
