Added device-based geo-fencing debug info support

Added debug information support for DBGF. Follow the steps below
to see the debug info.

1. Dial *#*#CMAS#*#* in the dialer to enable cell broadcast testing
   mode on a debug build.
2. Go to emergency alert settings->emergency alert history
3. On the right-upper corner, choose "show all messages".
4. Long press on the message and select show message details.

Test: Manual
Bug: 144152683
Change-Id: I791a8a482705ff2fd53f77a56c02969f020f888d