[TIMOB-28125] iOS: Add Ti.Geolocation constant "ACCURACY_REDUCED" support to iOS 13 and older

*Summary:* As of Titanium 9.2.0, we added Ti.Geolocation constant [ACCURACY_REDUCED](https://docs.appcelerator.com/platform/latest/#!/api/Titanium.Geolocation-property-ACCURACY_REDUCED) which is only supported on iOS 14 and higher. Attempting to use it on older iOS versions will cause a crash. This is by design, but it would better to support this constant on older iOS versions to make the permission handling code easier to write. *Proposal:* On iOS versions older than 14, Titanium should fallback to using ACCURACY_LOW when [Ti.Geolocation.accuracy](https://docs.appcelerator.com/platform/latest/#!/api/Titanium.Geolocation-property-accuracy) is assigned the ACCURACY_REDUCED constant. This is the closest equivalent. *Note:* We plan on adding all of the iOS only accuracy constants to Android via ticket [TIMOB-28117] for parity.