Add label and tone for WIFI_LOST disconnect cause.

The description was set already, but Dialer tends to ignore disconnect
messages if the label is not set.  Also ensuring there is a tone set.

Test: Added new unit test to verify correct disconnect cause when
WIFI is lost.
Bug: 149190578
Fixes: 153376158

Change-Id: I6fd2b9f736e94390bd75914fbdc2a7e92de31268
2 files changed