Added sync update database support

Added a config allowing updating subscription
database synchronously or asynchronously.

Test: atest FrameworksTelephonyTests
Bug: 239607619
Merged-In: I639a73a2213eb4a3030ce1398c441a552ab654cf
Change-Id: I639a73a2213eb4a3030ce1398c441a552ab654cf
1 file changed