Add Int32EnumTypeAnnotation to codegen schema

Summary:
Adds schema to allow for Int32Enums in the codegen.

All of the non-schema updates here are flow fixes, the code there is implemented in the next diffs

Reviewed By: JoshuaGross

Differential Revision: D17158026

fbshipit-source-id: b5a6871225771c3c97a43a901d5f8e51c44f35c8

packages/react-native-codegen/src/generators/components/GeneratePropsJavaInterface.js

@@ -88,6 +88,9 @@ function getJavaValueForProp(prop: PropTypeShape, imports): string {
     case 'StringEnumTypeAnnotation':
       addNullable(imports);
       return '@Nullable String value';
+    case 'Int32EnumTypeAnnotation':
+      addNullable(imports);
+      return '@Nullable Integer value';
     default:
       (typeAnnotation: empty);
       throw new Error('Received invalid typeAnnotation');