fix: linkedin issuer override

[hperl]

This fixes the linkedin provider, which now reports the correct issuer URL.

Related issue(s)

Checklist

• I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change
  introduces a new feature.
• I am following the
  contributing code guidelines.
• 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 the 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 or changed the documentation.

Further Comments

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.04%. Comparing base (660f330) to head (6c51e2c).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3875      +/-   ##
==========================================
- Coverage   78.05%   78.04%   -0.02%     
==========================================
  Files         360      360              
  Lines       25205    25197       -8     
==========================================
- Hits        19675    19665      -10     
  Misses       4027     4027              
- Partials     1503     1505       +2     

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