feat(Cell): add icon-prefix prop (#5666)

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

@@ -12,6 +12,11 @@ exports[`arrow direction 1`] = `
     <!----></i></div>
 `;
 
+exports[`icon-prefix prop 1`] = `
+<div class="van-cell"><i class="my-icon my-icon-success van-cell__left-icon">
+    <!----></i></div>
+`;
+
 exports[`render slot 1`] = `
 <div class="van-cell">Custom Icon<div class="van-cell__title">Custom Title<div class="van-cell__label">Custom Label</div>
   </div>Custom Extra</div>

src/cell/test/index.spec.js

@@ -67,3 +67,14 @@ test('CellGroup title slot', () => {
 
   expect(wrapper).toMatchSnapshot();
 });
+
+test('icon-prefix prop', () => {
+  const wrapper = mount(Cell, {
+    propsData: {
+      iconPrefix: 'my-icon',
+      icon: 'success',
+    },
+  });
+
+  expect(wrapper).toMatchSnapshot();
+});