Tabs: fix "With tab icons" Storybook example

[ciampo]

What?

Fixes #63271

Tweaks the "With tab icons" Storybook example for the Tabs component so that tab styles are correct

Why?

Previously, the example was using the Button component, which would being in its own styles, overriding the Tabs.Tab styles.

How?

By switching from Button to using the individual Tooltip and Icon components, as suggested by @mirka in #63271 (comment)

Testing Instructions

• Load the "With tab icons" Storybook example for the Tabs component
• Play around with the component, using the keyboard to select different tabs
• Make sure that focus styles look correct, that tab selection works as expected, and the tooltip shows as expected while hovering or focussing a tab

Screenshots or screencast

Before (trunk)	After (this PR)

[github-actions]

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Co-authored-by: ciampo <mciampini@git.wordpress.org>
Co-authored-by: mirka <0mirka00@git.wordpress.org>

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[mirka]

Works as expected, thanks!