No. There isn't a part of the board that houses the aux sound that you can just take off or anything. And since there isn't a way to access the soundfont itself (like via an SD card), you couldn't replace it with silence.
On the saber that you accidentally keep triggering the aux sound, is the button on the momentary switch flush or does it stick up above the switch housing? Having one that is flush will help prevent this, as would a switch that requires a bit more pressure to activate, like the ones I got from a vaping supplier that posted in this
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