bug: Fix modal close button storybook example

[ahmadJT]

Description

• updated the close button storybook example so the modal closes on click

Markup:

Issue

#3995

export const CloseButton: StoryFn = () => ({
  components: { VaModal },
  data () {
    return {
      show: false,
    }
  },
  template: `
    <button @click="show = true">
      show modal
    </button>
    <VaModal :model-value="show" @cancel="show = false" :close-button="true">
      Lorem ipsum dolor sit amet consectetur adipisicing elit. Quisquam, voluptatum. Lorem ipsum dolor sit amet consectetur adipisicing elit. Quisquam, voluptatum.
    </VaModal>
  `,
})

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement/refactoring (non-breaking change that doesn't add any feature but make things better)