feat/add disabledBackgroundColor API for Button (#899)

* feat/add disabledBackgroundColor API for Button

* clean code

Author: lidord-wix

src/components/button/index.tsx

@@ -60,6 +60,10 @@ export type ButtonPropTypes = TouchableOpacityProps &
      * Color of the button background
      */
     backgroundColor?: string;
+    /**
+     * Color of the disabled button background
+     */
+    disabledBackgroundColor?: string;
     /**
      * Size of the button [large, medium, small, xSmall]
      */
@@ -250,12 +254,12 @@ class Button extends PureComponent<Props, ButtonState> {
 
   getBackgroundColor() {
     const {backgroundColor: themeBackgroundColor, modifiers} = this.props;
-    const {disabled, outline, link, backgroundColor: propsBackgroundColor} = this.props;
+    const {disabled, outline, link, disabledBackgroundColor, backgroundColor: propsBackgroundColor} = this.props;
     const {backgroundColor: stateBackgroundColor} = modifiers;
 
     if (!outline && !link) {
       if (disabled) {
-        return ThemeManager.CTADisabledColor;
+        return disabledBackgroundColor || ThemeManager.CTADisabledColor;
       }
 
       return propsBackgroundColor || stateBackgroundColor || themeBackgroundColor || Colors.blue30;