fix(sbb-calendar): using keyboard navigation loses focus

[MarioCastigliano]

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 #2300

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:

• Fix focus loss during keyboard navigation
• Fix data-now="" being incorrectly interpreted as "Jan 1, 1970"

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

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (main@f239990). Click here to learn what that means.

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Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2354   +/-   ##
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  Coverage        ?   93.68%           
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  Files           ?      228           
  Lines           ?    23470           
  Branches        ?     2059           
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  Hits            ?    21989           
  Misses          ?     1442           
  Partials        ?       39           

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[TomMenga]

It looks legit and good to me.
I just have a doubt on the .?query... thing

[jeripeierSBB]

LGTM

Changes applied