fix(client): fix distorted RNNoise output during mono capture

[codeHusky]

Fix sourced from remjey/mumble@f16b47c

When the input signal is very loud and clipping, the output of RNNoise is very distorted, way more than the input signal.

This is because RNNoise outputs a signal that is unbounded and sometimes goes over the limits of the signed 16-bit signal that Mumble uses internally. When Mumble converts RNNoise output signal to 16-bit, integer overflow occurs and creates a very loud distortion.

Mumble now clamps the output of RNNoise which results in a signal that is not more distorted than the input signal.

This code clamps the values sent to RNNoise to prevent loud overdrive clipping, fixing #370