Return messageId for generic and text Conversation.send (#119)

At the moment only EncodedContent returns the messageId as result and other send function does not.

Updated send function result to be consistent across all overloads.

Author: gvoltr

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

@@ -107,22 +107,22 @@ sealed class Conversation {
         }
     }
 
-    fun send(prepared: PreparedMessage) {
-        when (this) {
+    fun send(prepared: PreparedMessage): String {
+        return when (this) {
             is V1 -> conversationV1.send(prepared = prepared)
             is V2 -> conversationV2.send(prepared = prepared)
         }
     }
 
-    fun <T> send(content: T, options: SendOptions? = null) {
-        when (this) {
+    fun <T> send(content: T, options: SendOptions? = null): String {
+        return when (this) {
             is V1 -> conversationV1.send(content = content, options = options)
             is V2 -> conversationV2.send(content = content, options = options)
         }
     }
 
-    fun send(text: String, sendOptions: SendOptions? = null, sentAt: Date? = null) {
-        when (this) {
+    fun send(text: String, sendOptions: SendOptions? = null, sentAt: Date? = null): String {
+        return when (this) {
             is V1 -> conversationV1.send(text = text, sendOptions, sentAt)
             is V2 -> conversationV2.send(text = text, sendOptions, sentAt)
         }