I'm sure it was cleaned to a reasonable standard. We can't know for certain without knowing where the condom was, but since the family spent the night and the kid didn't find it until the next morning it's safe to assume it wasn't out in the open.
There are places under and behind furniture that kids can reach but adults can't. The maids don't remove the furniture to clean the room, and it's not reasonable to expect them to (unless you want to pay them a lot more). Leaving your child unattended in your own home (which should be reasonable child-proofed) is one thing, but a hotel room is a different situation entirely. There are plenty of dangers to small children in hotel rooms besides used condoms.
The maids can't be expected to catch everything that could fall under/behind the furniture, and parents should be more careful in a hotel than they need to be in their own home.