Fixes double-submit issue

app/src/main/java/de/kuschku/quasseldroid_ng/ui/chat/ChatActivity.kt

@@ -164,15 +164,18 @@ class ChatActivity : ServiceBoundActivity(), SharedPreferences.OnSharedPreferenc
   }
 
   private fun send() {
+    val text = chatline.text
+    if (text.isNotBlank()) {
       viewModel.session { session ->
         viewModel.getBuffer().let { bufferId ->
           session.bufferSyncer?.bufferInfo(bufferId)?.also { bufferInfo ->
             session.rpcHandler?.sendInput(
-            bufferInfo, ircFormatSerializer.toEscapeCodes(chatline.text)
+              bufferInfo, ircFormatSerializer.toEscapeCodes(text)
             )
           }
         }
       }
+    }
     chatline.setText("")
   }