Set topic to convoId instead of message ID

Author: richardhuaaa

library/src/main/java/org/xmtp/android/library/Group.kt

@@ -121,7 +121,7 @@ class Group(val client: Client, private val libXMTPGroup: FfiGroup) {
     fun decrypt(message: Message): DecryptedMessage {
         return DecryptedMessage(
             id = message.id.toHex(),
-            topic = message.id.toHex(),
+            topic = message.convoId.toHex(),
             encodedContent = message.decode().encodedContent,
             senderAddress = message.senderAddress,
             sentAt = Date()

library/src/main/java/org/xmtp/android/library/libxmtp/Message.kt

@@ -12,6 +12,9 @@ data class Message(val client: Client, private val libXMTPMessage: FfiMessage) {
     val id: ByteArray
         get() = libXMTPMessage.id
 
+    val convoId: ByteArray
+        get() = libXMTPMessage.convoId
+
     val senderAddress: String
         get() = libXMTPMessage.addrFrom