re #17486 - set _locationManager if auth skipped

Summary:
This fixes #17486

make sure locationManager is being set before continuing.

Used if !locationManager vs else on previous statement as we should NEVER enter this code without _locationManager set. Also the else version might experience issues if someone touches the auth code and doesn't check this case, so seems more "long term stable".

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This fixes #17486

1) Have a working geolocation demo
2) Add navigator.geolocation.setRNConfiguration({'skipPermissionRequests':true}); to your code. I added it to the constructor or componentWillMount for the app.
3) Observe that geolocation no longer works (times out)
4) Apply patch
5) Observe that geolocation works again

re #15096

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[IOS] [BUGFIX] [GeoLocation] - Fix skipPermissionRequests by setting _locationManager
Closes #17487

Differential Revision: D6718389

Pulled By: hramos

fbshipit-source-id: 08c1c9306b4d87cc40acdaa1550bb6df8345db02

Author: ngandhy

Libraries/Geolocation/RCTLocationObserver.m

@@ -158,6 +158,11 @@ - (void)beginLocationUpdatesWithDesiredAccuracy:(CLLocationAccuracy)desiredAccur
   if (!_locationConfiguration.skipPermissionRequests) {
     [self requestAuthorization];
   }
+  
+  if (!_locationManager) {
+    _locationManager = [CLLocationManager new];
+    _locationManager.delegate = self;
+  }
 
   _locationManager.distanceFilter  = distanceFilter;
   _locationManager.desiredAccuracy = desiredAccuracy;