tree-wide: acquire /dev/console lock around any attempts to reset TTY

src/core/exec-invoke.c

@@ -660,6 +660,10 @@ static int setup_confirm_stdio(
         if (fd < 0)
                 return fd;
 
+        _cleanup_close_ int lock_fd = lock_dev_console();
+        if (lock_fd < 0)
+                log_debug_errno(lock_fd, "Failed to lock /dev/console, ignoring: %m");
+
         r = chown_terminal(fd, getuid());
         if (r < 0)
                 return r;