fix(web): json_encode for input enter in /user/msg

This commit fixes #79.
Ref: https://huntr.dev/bounties/a2b63a25-385f-4f4e-b790-d910b90718f7/

web/app/controllers/user_msg.php

@@ -151,7 +151,7 @@ function deleteMsg($msgId) {
 	$.ajaxSetup({async:false});
 	refreshConversations();
 	<?php if (isset($_GET['enter'])): ?>
-	enterConversation("<?= $_GET['enter'] ?>");
+	enterConversation(<?= json_encode($_GET['enter']) ?>);
 	<?php endif ?>
 });
 </script>