feat(radio): refactor of switch handling to better support customisable switches (#6095)

Co-authored-by: philmoz <phil.a.mitchell@gmail.com>
Co-authored-by: 3djc <3djc@gh.com>
Co-authored-by: elecpower <elecpower@users.noreply.github.com>

radio/src/storage/sdcard_yaml.cpp

@@ -181,6 +181,7 @@ const char * loadRadioSettings()
 #endif
 
     adcCalibDefaults();
+    generalDefaultSwitches();
 
     const char* error = loadRadioSettingsYaml(true);
     if (!error) {
@@ -191,8 +192,6 @@ const char * loadRadioSettings()
     return error;
 }
 
-
-
 struct yaml_checksummer_ctx {
     FRESULT result;
     uint16_t checksum;
@@ -341,6 +340,10 @@ const char * readModelYaml(const char * filename, uint8_t * buffer, uint32_t siz
     memset(buffer,0,size);
 
     if (init_model) {
+#if defined(FUNCTION_SWITCHES)
+      extern void initCustomSwitches();
+      initCustomSwitches();
+#endif
       auto md = reinterpret_cast<ModelData*>(buffer);
 #if defined(FLIGHT_MODES) && defined(GVARS)
       // reset GVars to default values