Fail Safe for circuit, when input is removed
What you want to do is not possible.  The datasheet shows the ULN2003A to have open collector outputs.  That means it only switches between open and actively driven low.  Open is the same as disconnected.  Your circuit therefore can't tell the difference between open and disconnected.

To make this work, you need the off state to be when the ULN is open, and active when it is pulling low.  That way, disconnected will cause off, not active.

The ULN does have some diodes connected to the output in addition to the open collector.  With more circuitry and some cleverness you could detect the presence of one of the diodes.  However, that's quite a kludge around a fundamentally bad architecture.  It is better to fix the real problem instead of kludging around it.