You'd probably just have to measure it with a multimeter. It's not something I've seen published for similar boards either.
Current consumption should be insignificant compared to the Arduino.
I haven't seen a schematic for this board but a condenser microphone typically requires about 1mA. The LEDs could take 5 or 10mA when on. The op-amp and bias resistors probably add a few more mA.
If you connect a "load" (a low impedance/resistance) to the sound sensor's output that will increase current. An Arduino input has super-high resistance/impedance and it essentially draws zero current.