Add value property to legend Formatter type (recharts#3668)

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## Description

Add a property to `DefaultLegendContent` type `Formatter` - `value?:
any;`. This will provide type safety when using legend formatter with a
pie chart.

## Related Issue
recharts#3666
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## Motivation and Context
This solves a TS issue where when passing a formatter function to a
legend inside a pie chart, `entry.payload` will not include the payload
value.
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## How Has This Been Tested?
`npm run test`, `npm run lint` & `npm run build-types` all passed.
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## Screenshots (if appropriate):

## Types of changes

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- [x] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)

## Checklist:

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- [x] My code follows the code style of this project.
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- [ ] I have added tests to cover my changes.
- [x] All new and existing tests passed.

src/component/DefaultLegendContent.tsx

@@ -28,6 +28,7 @@ export type Formatter = (
     color?: string;
     payload?: {
       strokeDasharray: ReactText;
+      value?: any;
     };
   },
   index: number,
@@ -40,6 +41,7 @@ export interface Payload {
   color?: string;
   payload?: {
     strokeDasharray: ReactText;
+    value?: any;
   };
   formatter?: Formatter;
   inactive?: boolean;