Echo cancellation

Is this something we could add to callaudiod (f.e. when switching to the audio profiles)?

On the L5 echo cancellation is handled by wys:

https://source.puri.sm/Librem5/wys/-/blob/master/src/wys-audio.c#L971

https://source.puri.sm/Librem5/wys/-/blob/master/src/wys-audio.c#L985

Those changes (from what I understand) make use of the environment variable PULSE_PROP_FILTER.want=echo-cancel