SDK / exoplayer

The main user of the Util method is the bandwidth meter to set the
initial network type. If this is the first call to the
NetworkTypeObserver, then we should also allow the first update to
a known network type even if no reset on network type is activated.

The other uses are analytics listeners that check the network type
at certain events. This can just use the lookup method of the
NetworkTypeObserver.

PiperOrigin-RevId: 363670771