Compact aidl exception message am: 3c9cbc6cbe

Original change: https://googleplex-android-review.googlesource.com/c/platform/vendor/widevine/+/21874559

Change-Id: I29c9974f3a77433bed9a942137dec6c66f06b49a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

libwvdrmengine/src/Utils.cpp

@@ -160,6 +160,7 @@ CryptoSessionApi getCryptoSessionMethodEnum(const std::string& method) {
       jsonMsg["errorMessage"] = msg;
     }
     Json::FastWriter writer;
+    writer.omitEndingLineFeed();
     return ::ndk::ScopedAStatus::fromServiceSpecificErrorWithMessage(
         err, writer.write(jsonMsg).c_str());
   }