feat(gps): Do not start gps if lora region is unset (#10386)

* Disable gps thread on startup if lora region is unset

There is little reason to waste battery on the gps if the data cannot
yet be used.

* fix goobered merge

Refactor GPS enabling logic and remove duplicate code.

* trunk

---------

Co-authored-by: Jonathan Bennett <jbennett@incomsystems.biz>

src/gps/GPS.cpp

@@ -2257,6 +2257,11 @@ int32_t GPS::disable()
     return INT32_MAX;
 }
 
+bool GPS::isEnabled()
+{
+    return enabled;
+}
+
 void GPS::toggleGpsMode()
 {
     if (config.position.gps_mode == meshtastic_Config_PositionConfig_GpsMode_ENABLED) {

src/gps/GPS.h

@@ -98,6 +98,9 @@ class GPS : private concurrency::OSThread
     // Disable the thread
     int32_t disable() override;
 
+    // Returns if the thread is enabled
+    bool isEnabled();
+
     // toggle between enabled/disabled
     void toggleGpsMode();