fix(ios, deviceType): support iOS-compiled app running on macOS (#1181)

* run time check for iOS app running on macOS.

* Fix issue with iOS version detection. @avaliable has to be in a stand along if statement.

Co-authored-by: John Schember <jschember@monetra.com>

ios/RNDeviceInfo/RNDeviceInfo.m

@@ -111,7 +111,16 @@ - (DeviceType) getDeviceType
 {
     switch ([[UIDevice currentDevice] userInterfaceIdiom]) {
         case UIUserInterfaceIdiomPhone: return DeviceTypeHandset;
-        case UIUserInterfaceIdiomPad: return TARGET_OS_MACCATALYST ? DeviceTypeDesktop : DeviceTypeTablet;
+        case UIUserInterfaceIdiomPad:
+            if (TARGET_OS_MACCATALYST) {
+                return DeviceTypeDesktop;
+            }
+            if (@available(iOS 14.0, *)) {
+                if ([NSProcessInfo processInfo].isiOSAppOnMac) {
+                    return DeviceTypeDesktop;
+                }
+            }
+            return DeviceTypeTablet;
         case UIUserInterfaceIdiomTV: return DeviceTypeTv;
         case UIUserInterfaceIdiomMac: return DeviceTypeDesktop;
         default: return DeviceTypeUnknown;