fix: stories with label bold for sbb-checkbox and sbb-radio-button

[DavideMininni-Fincons]

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the pull request tracker for a Pull Request (PR) that matches the one I want to submit, without success.

Issue

This PR Closes #2498

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)

See Review Guidelines for more information what is checked during review process.

Changes

Changes in this pull request:

• add stories with bold label for sbb-checkbox and sbb-radio-button

Browsers

I tested the build on the following browsers:

• Firefox Desktop
• Chrome Desktop
• Edge Desktop
• Safari Desktop
• Chrome Mobile
• Safari Mobile

Screen readers

I tested the build on the following browsers:

• JAWS Firefox Desktop
• JAWS Chrome Desktop
• NVDA Firefox Desktop
• NVDA Chrome Desktop
• VoiceOver Safari Desktop
• VoiceOver Chrome Desktop
• VoiceOver Safari Mobile
• Android Accessibility Suite Chrome Mobile

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

Does this introduce a breaking change?

• Yes
• No

Other information

[jeripeierSBB]

LGTM, not sure if we need also an entry in readme files?

[TomMenga]

LGTM 👍

I'm not sure if having the bold param in storybook might be confusing (they might think there is a bold attribute)
Maybe add an example in the readme?

[DavideMininni-Fincons]

@TomMenga @jeripeierSBB
i'll add a note in the readme; maybe i can change the bold param with something like 'boldLabel'?

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (main@535c213). Click here to learn what that means.

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2528   +/-   ##
=======================================
  Coverage        ?   93.19%           
=======================================
  Files           ?      301           
  Lines           ?    24921           
  Branches        ?     2029           
=======================================
  Hits            ?    23225           
  Misses          ?     1667           
  Partials        ?       29           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[jeripeierSBB]

LGTM, thanks for re working