Activating TX Low Pass Filter in Second IF IC (#1470)

* Activating TX Low Pass Filter in Second IF IC
* solving PR conversation revisions
* Final TX LPF decision for ADSB_TX
* Small comments correction.
* Added set TX LPF also  in APRS, BurgerPgr,Jammer

firmware/application/apps/soundboard_app.cpp

@@ -120,6 +120,7 @@ void SoundBoardView::start_tx(const uint32_t id) {
     );
     baseband::set_sample_rate(sample_rate);
 
+    transmitter_model.set_baseband_bandwidth(1'750'000);  // the Minimum TX LPF  1M75 is fine.
     transmitter_model.enable();
 
     tx_view.set_transmitting(true);