use new config override_dnd to replace override_dnd_default

Previously we are using override_dnd_default to control if alerts
audio should ignore DND settings. override_dnd_default is the default
value of the overrinding dnd settings(sharedpred). updating
override_dnd_default value per carrier requirements won't take effect
in OTA as we persists user preferences. We should use a separate config
to control override dnd in general rather than using sharedpreference.
The new logic: 1) override_dnd_default only serve the purpose of default
settings values. Read override_dnd sharedpreference value only when the toggle
is visible 2) range.mOverrideDND is the per channel config 3)
override_dnd is the main config for all channels

Bug: 169452408
Test: Manual
Change-Id: I9b72fdf84cdabf67f545abd14a7c53c6b6af6cae
11 files changed