fix color pick type using react-color types (#1915)

src/components/side-panel/layer-panel/custom-picker.tsx

@@ -20,27 +20,18 @@
 
 import React, {Component} from 'react';
 import styled, {withTheme} from 'styled-components';
-import {SketchPicker} from 'react-color';
+import {SketchPicker, ColorChangeHandler} from 'react-color';
 import onClickOutside from 'react-onclickoutside';
 import {createSelector} from 'reselect';
 // This was put in because 3rd party library react-color doesn't yet cater for customized color of child component <SketchField> which contains HEX/RGB input text box
 // Issue raised: https://github.com/casesandberg/react-color/issues/631
 
-type SketchPickerValue = {
-  hsl: {h: number; s: number; l: number; a: number};
-  hex: string;
-  rgb: {r: number; g: number; b: number; a: number};
-  hsv: {h: number; s: number; v: number; a: number};
-  oldHue: number;
-  source: string;
-};
-
 type CustomPickerProps = {
   color: string;
   theme: {
     panelBackground: string;
   };
-  onChange: (v: SketchPickerValue) => void;
+  onChange: ColorChangeHandler;
   onSwatchClose: () => void;
 };