fix(examples): improve theme switch in finefood-antd example

[Ankitjordan]

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Bugs / Features

• Related issue(s) linked
• Tests for the changes have been added
• Docs have been added / updated
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What is the current behavior?

The theme toggle button in the header was not properly centered, causing a visual misalignment. Additionally, there was a noticeable flickering effect and delay when switching between light and dark modes, making the transition feel laggy.

What is the new behavior?

• Fixed the alignment of the theme toggle icon for a cleaner UI
• Removed flickering and delay during theme transitions
• Improved the theme switching logic using document.startViewTransition for a smoother and more polished experience

Notes for reviewers

• Changes are limited to the finefoods-antd example
• No changes were made to core packages

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Latest commit: 21a6240

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