[SettingsProvider] do not crash the system if config settings files are broken

Tolerate config flags' serialization/deserialization failures because they can be sync'd after boot.

BUG: 295555884
Test: manually push a broken config file onto device and reboot
Merged-In: I9851991b4a225f2941708d37d2ad9507d7c432f8
Change-Id: I9851991b4a225f2941708d37d2ad9507d7c432f8
(cherry picked from commit 2ba72c06)