fix: hover effect (#3027)

change `width` to `min-width` in order to be compatible with the width of the globalheader's account is more than 160px

src/components/GlobalHeader/index.less

@@ -29,7 +29,7 @@
     margin-right: 8px;
   }
   :global(.ant-dropdown-menu-item) {
-    width: 160px;
+    min-width: 160px;
   }
 }