luci-app-mosquitto: update tls versions for bridges as well

Earlier we updated the options list for tls versions for the broker's
own listeners, but we missed the list of tls versions used when
connecting to remote brokers.

Fixes: a7b1d63e

 drop tls1.0, add tls1.3
Signed-off-by: Karl Palsson <karlp@etactica.com>