fix: properly set default value for checkboxes

[jonas-jonas]

Related Issue or Design Document

Checklist

• I have read the contributing guidelines and signed the CLA.
• I have referenced an issue containing the design document if my change introduces a new feature.
• I have read the security policy.
• I confirm that this pull request does not address a security vulnerability.
  If this pull request addresses a security vulnerability,
  I confirm that I got approval (please contact security@ory.sh) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works.
• I have added the necessary documentation within the code base (if appropriate).

Further comments

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 43.69%. Comparing base (071c0ff) to head (43a1be9).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #314      +/-   ##
==========================================
- Coverage   43.73%   43.69%   -0.05%     
==========================================
  Files         135      135              
  Lines        1932     1934       +2     
  Branches      279      280       +1     
==========================================
  Hits          845      845              
- Misses       1080     1082       +2     
  Partials        7        7              

Components	Coverage Δ
@ory/elements-react	38.09% <0.00%> (-0.05%)	⬇️
@ory/nextjs	65.97% <ø> (ø)