fix(TabBar): 修复 IOS 上安全区域适配的问题

close #1293,#1289

Author: juzi214032

src/tab-bar/index.less

@@ -1,3 +1,5 @@
+@import "../../config/styles/_mixins.less";
+
 // 红点颜色
 @red-dot-color: #ff474b;
 @component: lu-tab-bar;
@@ -15,12 +17,14 @@
   background-color: white;
   background-size: 100% 100%;
   background-repeat: no-repeat;
+  .safe-area-inset-bottom();
 }
 
 .@{component}__item-wrapper {
   display: flex;
   height: 100%;
   justify-content: center;
+  .safe-area-inset-bottom();
 }
 
 .@{component}__item-container {