docs: convert examples to be functional components

[github-actions[bot]]

size-limit report

Path	Size
bundle-size/dist/Button.size.js	54.01 KB (0%)
bundle-size/dist/Icon.size.js	27.33 KB (0%)
bundle-size/dist/Image.size.js	49.58 KB (0%)
bundle-size/dist/Modal.size.js	62.54 KB (0%)
bundle-size/dist/Portal.size.js	37.18 KB (0%)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (5646905) 99.50% compared to head (6b54e0b) 99.50%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #4453 +/- ## ======================================= Coverage 99.50% 99.50% ======================================= Files 186 186 Lines 3466 3466 ======================================= Hits 3449 3449 Misses 17 17 ```

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