Update the format of RCS provisioning config XML

Bug: 184275686
Test: atest FrameworksTelephonyTests:com.telephony.ims.RcsConfigTest
Test: atest TeleServiceTests:com.android.phone.RcsProvisioningMonitorTest
Test: atest CtsTelephonyTestCases:android.telephony.ims.cts.ImsServiceTest
Change-Id: I7df3c660326c6bee3db4a4d3a032ce8f1941b15b