修复placement: bottom模式样式覆盖造成的显示Bug (#143)

Co-authored-by: 啊 <[email protected]>

Author: xintiaobrother

assets/index.less

@@ -171,7 +171,8 @@
     }
   }
   &-bottom {
-    bottom:0;
+    top: unset;
+    bottom: 0;
     .@{drawer} {
       &-content-wrapper {
         bottom: 0;