Override button padding

### Package

v4.x

### Description

Hi guys,

I'm trying to override the default button padding, but for some reason this is not working. Am I doing something wrong?

```ts
export default defineAppConfig({
  ui: {
    button: {
      variants: {
        size: {
          md: {
            base: "px-10 py-5",
          },
        },
      },
    },
  },
});
```