Due to b/174645163#6, remove Apn.KEY_PREFIX from incompatibilities.txt

ag/13640526 is to modify Apn#KEY_PREFIX from private to public.

Thus, to remove field android.telephony.CarrierConfigManager.Apn.KEY_PREFIX
from public/api/incompatibilities.txt.

Bug: 174645163
Test: metalava frameworks/base/core/api/current.txt \
         --format=v2 \
         --no-banner \
         --check-compatibility:api:released prebuilts/sdk/30/public/api/android-non-updatable.txt \
         --baseline:compatibility:released prebuilts/sdk/31/public/api/incompatibilities.txt
Change-Id: Ie6e47bb4236eb2bc8b458ad385c96007aec80ec2
1 file changed