chardev/char-pty: free pty_name in finalize

The pty_name field was added to PtyChardev state but never freed
on object finalize, leaking the allocated string.

Fixes: 1116f5176e ("chardev/char-pty: store pty_name into PtyChardev state")
Reported-by: Hui Peng <benquike@gmail.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-ID: <20261004-issue-4560-v1-19-ccbef537cbeb@redhat.com>

chardev/char-pty.c

@@ -215,6 +215,7 @@ static void char_pty_finalize(Object *obj)
         unlink(s->path);
         g_free(s->path);
     }
+    g_clear_pointer(&s->pty_name, g_free);
 
     pty_chr_state(chr, 0);
     object_unref(OBJECT(s->ioc));