feat: dynamic token issuer

[manuel-lang]

Use dynamic token issuer URL not applying a scheme and path if they are already provided.

Description

Integrate changes from SDK Generator.

Closes #136

Review Checklist

• I have clicked on "allow edits by maintainers".
• I have added documentation for new/changed functionality in this PR or in a PR to openfga.dev [Provide a link to any relevant PRs in the references section above]
• The correct base branch is being used, if not main
• I have added tests to validate that the change in functionality is working as expected

[rhamzeh]

Thank you :)

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.45%. Comparing base (172cd26) to head (0473adb).
Report is 1 commits behind head on main.

❌ Your project status has failed because the head coverage (70.45%) is below the target coverage (80.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #186   +/-   ##
=======================================
  Coverage   70.45%   70.45%           
=======================================
  Files         134      134           
  Lines       10806    10806           
=======================================
  Hits         7613     7613           
  Misses       3193     3193           

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