Add AIDL methods to override carrier package

This change introduces a Carrier Service Package override, ensuring that
CTS can export a CarrierService, and set itself as the carrier service.

The requirement for the application to also be carrier-privileged still
stands, but omits the SIM-certificate-match requirement, instead
allowing carrierConfig based certificates + carrier service package
override as a sufficient gate (which critically need to both be doable
with the CTS Shell permission identity)

Bug: 266904760
Test: Manually tested with a demo CTS build, will be used for Core
      Networking CTS tests
Change-Id: I9c31e19dd122123e8e102c901efaa99b2c729635

telephony/java/com/android/internal/telephony/ITelephony.aidl

@@ -1841,6 +1841,22 @@ interface ITelephony {
     void setCarrierTestOverride(int subId, String mccmnc, String imsi, String iccid, String gid1,
             String gid2, String plmn, String spn, String carrierPrivilegeRules, String apn);
 
+    /**
+     * Forcibly sets a package as a carrier provisioning package.
+     *
+     * This override is ephemeral, and will disappear upon phone process restart (including
+     * device reboot).
+     *
+     * WARNING: This API is meant for testing purposes only. This enables automated testing for
+     * cases where the carrier service package is used as a permissioning gate for features such as
+     * restricted carrier network access (restricted APNs and Merged Carrier Wifi)
+     *
+     * @param carrierServicePackage The package that should be marked as the carrier service
+     *     package, or {@code null} to disable the override.
+     */
+    void setCarrierServicePackageOverride(int subId, String carrierServicePackage,
+                String callingPackage);
+
     /**
      * A test API to return installed carrier id list version.
      */