Don't write back uninitialized features on onGlobalExit

src/main/cms/cms_menu_blackbox.c

@@ -80,10 +80,12 @@ static long cmsx_Blackbox_FeatureRead(void)
 
 static long cmsx_Blackbox_FeatureWriteback(void)
 {
+    if (featureRead) {
         if (cmsx_FeatureBlackbox)
             featureSet(FEATURE_BLACKBOX);
         else
             featureClear(FEATURE_BLACKBOX);
+    }
 
     return 0;
 }

src/main/cms/cms_menu_ledstrip.c

@@ -53,10 +53,12 @@ static long cmsx_Ledstrip_FeatureRead(void)
 
 static long cmsx_Ledstrip_FeatureWriteback(void)
 {
+    if (featureRead) {
         if (cmsx_FeatureLedstrip)
             featureSet(FEATURE_LED_STRIP);
         else
             featureClear(FEATURE_LED_STRIP);
+    }
 
     return 0;
 }

src/main/cms/cms_menu_vtx.c

@@ -52,10 +52,12 @@ static long cmsx_Vtx_FeatureRead(void)
 
 static long cmsx_Vtx_FeatureWriteback(void)
 {
+    if (featureRead) {
         if (cmsx_featureVtx)
             featureSet(FEATURE_VTX);
         else
             featureClear(FEATURE_VTX);
+    }
 
     return 0;
 }