Dynamically showing "driving mode"

Dynamically showing "driving mode" in "Connection preferences" summary.
In cl/196700988, when driving mode is available/not available will using
Settings.System to set flag.
Example :
driving mode is available : Settings.System.putInt(mContentResolver,
DRIVING_MODE_SETTINGS_ENABLED, 1)
driving mode is not available : Settings.System.putInt(mContentResolver,
DRIVING_MODE_SETTINGS_ENABLED, 0);

This CL using Settings.System to get driving mode state that used to dynamically
showing "driving mode"

Bug: 79299421
Test: make -j50 RunSettingsRoboTests ROBOTEST_FILTER=AdvancedConnectedDeviceControllerTest
Change-Id: I702fa4fbc752c7b470184cf58f2e604f9f28c057
Merged-In: I702fa4fbc752c7b470184cf58f2e604f9f28c057