Fix bad content types when sending unencrypted media

changelog.d/7519.bugfix

@@ -0,0 +1 @@
+Voice Broadcast - Fix error on voice messages in unencrypted rooms

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/content/UploadContentWorker.kt

@@ -408,7 +408,7 @@ internal class UploadContentWorker(val context: Context, params: WorkerParameter
             newAttachmentAttributes: NewAttachmentAttributes
     ) {
         localEchoRepository.updateEcho(eventId) { _, event ->
-            val content: Content? = event.asDomain().content
+            val content: Content? = event.asDomain(castJsonNumbers = true).content
             val messageContent: MessageContent? = content.toModel()
             // Retrieve potential additional content from the original event
             val additionalContent = content.orEmpty() - messageContent?.toContent().orEmpty().keys