update to use the phone number parser of the mainline module according to the flag.

Bug: 418123484
Test: atest ImsPhoneTest, ImsServiceTest (by changing two flag values, enable_phone_number_service and phone_number_parsing_api)
Flag: com.android.internal.telephony.flags.enable_phone_number_parsing_api

Change-Id: I8cf7e46e02fdfba0a1c8e084f6b5d581d6dbaa60