Reset cell broadcast config cache on radio off or sub changed

The cell broadcast config may be dropped by modem when radio
off or subscription changed. In this case, the cache will be
reset to make sure the config will be set again when the api
is called by the cell broadcast module.

Bug: 266702656
Test: atest com.android.internal.telephony.GsmCdmaPhoneTest
Test: manual
Change-Id: I241a84aa6f23dcf16e958b6a01e649e6232e4722