[main] Ignore --hide-splash while deactivated

Since we ignore --show-splash, it makes no sense to process
--hide-splash either; in theory this does nothing already because
we won't have a boot_splash in our state - but that changes with
future patches and it's worth being safe.

src/main.c

@@ -667,6 +667,9 @@ dump_details_and_quit_splash (state_t *state)
 static void
 on_hide_splash (state_t *state)
 {
+  if (state->is_inactive)
+    return;
+
   if (state->boot_splash == NULL)
     return;