fix: wrap token handler in transaction

[hperl]

Fixes https://github.com/ory-corp/cloud/issues/5987

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[bot]]

Codecov Report

Attention: Patch coverage is 87.75510% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 76.31%. Comparing base (57096be) to head (e2d4900). Report is 4 commits behind head on master.

Files	Patch %	Lines
oauth2/handler.go	88.23%	2 Missing and 2 partials :warning:
persistence/sql/persister.go	66.66%	1 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #3730 +/- ## ========================================== + Coverage 76.22% 76.31% +0.08% ========================================== Files 134 134 Lines 10210 10212 +2 ========================================== + Hits 7783 7793 +10 + Misses 1910 1902 -8 Partials 517 517 ```

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