fix(Grid): info、dot prop not work when use icon slot (#4902)

src/grid/test/__snapshots__/index.spec.js.snap

@@ -9,6 +9,19 @@ exports[`icon-size prop 1`] = `
 </div>
 `;
 
+exports[`render icon-slot 1`] = `
+<div class="van-grid van-hairline--top">
+  <div class="van-grid-item" style="flex-basis: 25%;">
+    <div class="van-grid-item__content van-grid-item__content--center van-hairline">
+      <div class="van-grid-item__icon-wrapper">
+        <div></div>
+        <div class="van-info">1</div>
+      </div>
+    </div>
+  </div>
+</div>
+`;
+
 exports[`sqaure and set gutter 1`] = `
 <div class="van-grid" style="padding-left: 10rem;">
   <div class="van-grid-item van-grid-item--square" style="flex-basis: 50%; padding-top: 50%;">

src/grid/test/index.spec.js

@@ -50,3 +50,17 @@ test('icon-size prop', () => {
 
   expect(wrapper).toMatchSnapshot();
 });
+
+test('render icon-slot', () => {
+  const wrapper = mount({
+    template: `
+      <van-grid icon-size="10">
+        <van-grid-item info="1">
+          <div slot="icon" />
+        </van-grid-item>
+      </van-grid>
+    `
+  });
+
+  expect(wrapper).toMatchSnapshot();
+});