Capacitive sensor as drop-in replacement for mechanical button
simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. An NPN transistor will invert the logic signal from the touch sensor to the toy.

With 210 µA on a short it implies a pull-up of about 12 kΩ assuming a 3 V supply. An NPN transistor will be able to pull that low.