docs(docs): [skeleton] fix layout error in example

[xionkq]

Fix layout error in skeleton rendering-with-data example.

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[github-actions[bot]]

[github-actions[bot]]

Hello @xionkq, thank you for contributing to element-plus, please see our guideline to see how to make contribution

[github-actions[bot]]

🧪 Playground Preview: https://element-plus.run/?pr=17291 Please comment the example via this playground if needed.

[tolking]

Thank for your contribution