Fix duplicate [RCTConvert UIUserInterfaceStyle:]

Summary:
After https://github.com/facebook/react-native/pull/36122 we have two of these. This change consolidates the two category methods to be part of the base RCTConvert class instead.

Changelog:
[iOS][Fixed] - Fix duplicate [RCTConvert UIUserInterfaceStyle:]

Reviewed By: cipolleschi

Differential Revision: D44050929

fbshipit-source-id: dd216545e6194446c593cd693072f3959d653d7f

React/Base/RCTConvert.h

@@ -71,6 +71,7 @@ typedef NSURL RCTFileURL;
 + (UIKeyboardType)UIKeyboardType:(id)json;
 + (UIKeyboardAppearance)UIKeyboardAppearance:(id)json;
 + (UIReturnKeyType)UIReturnKeyType:(id)json;
++ (UIUserInterfaceStyle)UIUserInterfaceStyle:(id)json API_AVAILABLE(ios(12));
 #if !TARGET_OS_TV
 + (UIDataDetectorTypes)UIDataDetectorTypes:(id)json;
 #endif

React/Base/RCTConvert.m

@@ -501,6 +501,16 @@ RCT_ENUM_CONVERTER(
     UIReturnKeyDefault,
     integerValue)
 
+RCT_ENUM_CONVERTER(
+    UIUserInterfaceStyle,
+    (@{
+      @"unspecified" : @(UIUserInterfaceStyleUnspecified),
+      @"light" : @(UIUserInterfaceStyleLight),
+      @"dark" : @(UIUserInterfaceStyleDark),
+    }),
+    UIUserInterfaceStyleUnspecified,
+    integerValue)
+
 RCT_ENUM_CONVERTER(
     UIViewContentMode,
     (@{

React/CoreModules/RCTAlertManager.mm

@@ -32,20 +32,6 @@ RCT_ENUM_CONVERTER(
 
 @end
 
-@implementation RCTConvert (UIUserInterfaceStyle)
-
-RCT_ENUM_CONVERTER(
-    UIUserInterfaceStyle,
-    (@{
-      @"unspecified" : @(UIUserInterfaceStyleUnspecified),
-      @"light" : @(UIUserInterfaceStyleLight),
-      @"dark" : @(UIUserInterfaceStyleDark),
-    }),
-    UIUserInterfaceStyleUnspecified,
-    integerValue)
-
-@end
-
 @interface RCTAlertManager () <NativeAlertManagerSpec>
 
 @end

React/CoreModules/RCTAppearance.mm

@@ -69,20 +69,6 @@ NSString *RCTColorSchemePreference(UITraitCollection *traitCollection)
   return RCTAppearanceColorSchemeLight;
 }
 
-@implementation RCTConvert (UIUserInterfaceStyle)
-
-RCT_ENUM_CONVERTER(
-    UIUserInterfaceStyle,
-    (@{
-      @"light" : @(UIUserInterfaceStyleLight),
-      @"dark" : @(UIUserInterfaceStyleDark),
-      @"unspecified" : @(UIUserInterfaceStyleUnspecified)
-    }),
-    UIUserInterfaceStyleUnspecified,
-    integerValue);
-
-@end
-
 @interface RCTAppearance () <NativeAppearanceSpec>
 @end