Do not create data channels when they are not enabled
Do not create data channels when they are not enabled

"enableDataChannels" prevented the messages to be sent when the data
channels were disabled, but it did not prevent the data channels from
being created.

Signed-off-by: Daniel Calviño Sánchez <bd7629e975cc0e00ea7cda4ab6a120f2ee42ac1b@gmail.com>

nextcloud/spreed,nextcloud/spreed,nextcloud/spreed