4G+ RAT icon can not be displayed when back to 4G from 4G+

ServiceState#setIsUsingCarrierAggregation() does not work because
it sets current CA status to the copied instance but it does not set
to the original data. As a result, System UI cannot be determined
correctly whether to display the RAT icon as carrier aggregation
or not, the problem occurs.

To resolve the problem, apply the copied instance to the original data
by using addNetworkRegistrationInfo().

Test: manual - Checked that correct RAT icon is displayed according to
rat ratchet behavior.
Bug: 141276200

Change-Id: Ic9a26ff932647b09d8770304c3057b572afaf2a4