Strip space before sending messages

src/application/main-window.vala

@@ -57,6 +57,14 @@ public class MainWindow : Adw.ApplicationWindow
         var body = view.message_body;
         var attachment_guids = view.attachment_guids;
 
+        // Strip empty space at the beginning and end of the body
+        body = body.strip();
+
+        if (body.length == 0) {
+            GLib.warning("Message body is empty");
+            return;
+        }
+
         if (transcript_container_view.transcript_view.model == null) {
             GLib.warning("No conversation selected");
             return;