Fix NULL pointer dereferencing (#34)

Co-authored-by: SessionHero01 <SesshioHero01@getsession.org>
(cherry picked from commit 94e6f06)

Author: 2 people

library/src/main/cpp/protocol.cpp

@@ -54,7 +54,7 @@ static JavaLocalRef<jobject> serializeDecodedEnvelope(JNIEnv *env, const session
 
     return {env, env->NewObject(class_info.java_class, class_info.constructor,
                           serializeEnvelop(env, envelop.envelope).get(),
-                          envelop.pro ? nullptr : serializeDecodedPro(env, *envelop.pro).get(),
+                          envelop.pro ? serializeDecodedPro(env, *envelop.pro).get() : nullptr,
                           content.get(),
                           sender_ed25519.get(),
                           sender_x25519.get(),