fix(sd-jwt-vc): improve alignment with draft-03

[charsleysa]

Improves alignment with draft 03

• iat is no longer required
• iat can now be selective disclosed
• the header.typ value is now vc+sd-jwt

[cre8]

LGTM, thank you for the contribution @charsleysa

[lukasjhan]

Thank you :)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.02%. Comparing base (d097f8c) to head (8bd3e54).

❗ Current head 8bd3e54 differs from pull request most recent head 29f0728. Consider uploading reports for the commit 29f0728 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #175      +/-   ##
==========================================
- Coverage   98.03%   98.02%   -0.01%     
==========================================
  Files          23       23              
  Lines        2082     2081       -1     
  Branches      307      307              
==========================================
- Hits         2041     2040       -1     
  Misses         41       41              

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[lukasjhan]

@charsleysa Can you fix the lint failing on ci?

Run pnpm run format will fix the issue

[charsleysa]

@lukasjhan fixed!