cli_gps: use sensormanger to toggle gps on/off to keep state coherent

src/helpers/sensors/LocationProvider.h

@@ -21,5 +21,5 @@ public:
     virtual void begin() = 0;
     virtual void stop() = 0;
     virtual void loop() = 0;
-    virtual bool isActive() = 0;
+    virtual bool isEnabled() = 0;
 };

src/helpers/sensors/MicroNMEALocationProvider.h

@@ -78,7 +78,7 @@ public :
         }        
     }
 
-    bool isActive() override {
+    bool isEnabled() override {
         // directly read the enable pin if present as gps can be
         // activated/deactivated outside of here ...
         if (_pin_en != -1) {