fix: grid radio add white background (#2467)

Author: gimmyhehe

packages/theme/src/grid/radio.less

@@ -53,6 +53,7 @@
       margin: 1px;
       border: 1px solid var(--tv-Grid-radio-icon-color-selected);
       border-radius: 100%;
+      background: #fff;
 
       &::after {
         content: '';