Add Vbat Sag Compensation to UI

Remove empty white line

Improve ff and vbatSag functions change events

Tooltip reviewing

src/js/fc.js

@@ -461,6 +461,7 @@ var FC = {
             ff_interpolate_sp:          0,
             ff_smooth_factor:           0,
             ff_boost:                   0,
+            vbat_sag_compensation:      0,
         };
         ADVANCED_TUNING_ACTIVE = { ...ADVANCED_TUNING };