Customize the service class for Call barring

The service class is only set "SERVICE_CLASS_VOICE" in Call barring
settings, However, some carriers want to use other service class for
Call barring settings.
Therefore, changes the service class for Call barring to be customizable
by using CarrierConfig.

Test: manual - Checked that changes the service class for Call barring
by "KEY_CALL_BARRING_DEFAULT_SERVICE_CLASS_INT" value.
Test: auto - Passed TeleServiceTests
Bug: 161772958

Change-Id: I5945c7471df6ed9b93a1b368cb700582cd84a271
1 file changed