fix: improve sd-expandable a11y

[paulovareiro29]

Description:

Closes #1476

This PR addresses:

• Adjust sd-expandable spacings according to figma
• Reorder of sd-expandable dom order. (button first so it is targetable by keyboard first)
• Improvement of the sd-expandable template labels
• Added accessibility hints to sd-expandable

Definition of Reviewable:

• Documentation is created/updated
• Migration Guide is created/updated
• E2E tests (features, a11y, bug fixes) are created/updated

• Stories (features, a11y) are created/updated
• relevant tickets are linked

[changeset-bot]

🦋 Changeset detected

Latest commit: 1494f5f

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[github-actions]

🚀 Storybook has been deployed for branch fix_improve-sd-expandable-a11y

• View Storybook

[MartaPintoTeixeira]

Accessibility hints added in storybook were now added to figma.

[paulovareiro29]

Hi @MartaPintoTeixeira @coraliefeil ,
I have adjusted the spacings between the content and the button to look like figma. In figma there is a spacing of 16px. Previously, on implementation, there was none.