fix(afhds2): add missing txCompleted to prevent crash on NV14 (#7301)

Co-authored-by: raphaelcoeffic <1050031+raphaelcoeffic@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

radio/src/pulses/afhds2.cpp

@@ -95,4 +95,5 @@ const etx_proto_driver_t Afhds2InternalDriver = {
   .processData = afhds2ProcessData,
   .processFrame = nullptr,
   .onConfigChange = nullptr,
+  .txCompleted = modulePortSerialTxCompleted,
 };

radio/src/pulses/pulses.cpp

@@ -565,7 +565,7 @@ void pulsesSendNextFrame(uint8_t module)
     }
 
     // if previous frame not completed, skip this one
-    if (!drv->txCompleted(ctx)) return;
+    if (drv->txCompleted && !drv->txCompleted(ctx)) return;
 
     uint8_t channelStart = g_model.moduleData[module].channelsStart;
     int16_t* channels = &channelOutputs[channelStart];