Ctrl + Shift + C
Then type moveobjects on into the box at the top of the screen and press enter.
Go into build or buy mode, grab the toddler and put it somewhere on the floor. Go back into live mode. Problem solved

The toddler might flicker into and out of the pet bed when they start crawling or walking but will no longer be stuck there. You can do this for any sims stuck anywhere, like in a corner behind some chairs if your dining table is too close to the wall, etc.