On LILYGO T-TWR Plus the squelch was being controlled by AT1846s,
resulting in the squelch bar setting being completely ignored. Now we
are introducing the support for a new command of sa8x8-fw called
AT+AUDIO that controls the muting or unmuting of the speaker power
amplifier, enabling us to:
1. Disable AT1846s embedded squelch
2. Enable OpeRTX squelch
Also fixed a bug where the sa8x8-fw version was incorrectly checked.
AT+AUDIO requires sa8x8-fw version v1.3.0.r1, bumped version check in
OpenRTX.
TG-553
Niccolò Izzo