LilyGo T-Beam: added battery voltage reporting

src/helpers/TBeamBoard.h

@@ -75,7 +75,7 @@ public:
   }
 
   uint16_t getBattMilliVolts() override {
-    return 0;
+    return power.getBattVoltage();
   }
 
   const char* getManufacturerName() const override {