[styled-react-modal] update and export ModalProps interface (#35090)

* add missing prop to styled-react-modal

* fix lint errors

types/styled-react-modal/index.d.ts

@@ -1,6 +1,7 @@
-// Type definitions for styled-react-modal 1.1
+// Type definitions for styled-react-modal 1.2
 // Project: https://github.com/AlexanderRichey/styled-react-modal
 // Definitions by: Adam Lavin <https://github.com/Lavoaster>
+//                 Greg Perlman <https://github.com/gperl27>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.9
 
@@ -9,10 +10,11 @@ import { StyledComponent, AnyStyledComponent, CSSObject, InterpolationFunction }
 
 declare const BaseModalBackground: StyledComponent<'div', any>;
 
-interface ModalProps {
+export interface ModalProps {
   children?: React.ReactNode;
   isOpen: boolean;
   allowScroll?: boolean;
+  backgroundProps?: object;
   afterOpen?: () => void;
   afterClose?: () => void;
   beforeOpen?: Promise<void> | (() => void);

types/styled-react-modal/styled-react-modal-tests.tsx

@@ -29,6 +29,7 @@ const test2 = (
     <ModalProvider backgroundComponent={BackgroundComponent}>
         <Modal
             isOpen={true}
+            backgroundProps={{style: {padding: "20px"}}}
             onBackgroundClick={() => console.log('Background click!')}
             onEscapeKeydown={() => console.log('Background click!')}
             afterOpen={() => console.log('After Open!')}