Gradient - fix Android line spaces (#2957)

* Gradient - fix Android line spaces

* remove unused import

Author: Inbal-Tish

src/components/gradient/index.tsx

@@ -2,7 +2,6 @@ import isString from 'lodash/isString';
 import tinycolor from 'tinycolor2';
 import React, {useCallback, useMemo} from 'react';
 import {StyleSheet, StyleProp, ViewStyle} from 'react-native';
-import Constants from '../../commons/Constants';
 import {Colors} from '../../style';
 import View from '../view';
 
@@ -42,7 +41,7 @@ const Gradient = (props: GradientProps) => {
   const getStyle = useCallback((index: number) => {
     return {
       flex: 1,
-      marginLeft: Constants.isIOS ? -StyleSheet.hairlineWidth : 0,
+      marginLeft: -StyleSheet.hairlineWidth,
       backgroundColor: getBackgroundColor(index)
     };
   }, [getBackgroundColor]);

src/incubator/Slider/slider.api.json

@@ -61,7 +61,7 @@
       "description": "Custom render instead of rendering the track"
     },
     {"name": "thumbTintColor", "type": "string", "description": "Thumb color"},
-    {"name": "DisabledThumbTintColor", "type": "string", "description": "Disabled thumb color"},
+    {"name": "disabledThumbTintColor", "type": "string", "description": "Disabled thumb color"},
     {"name": "thumbStyle", "type": "ViewStyle", "description": "The thumb style"},
     {"name": "activeThumbStyle", "type": "ViewStyle", "description": "The active (during press) thumb style"},
     {