resource_token: fix expires property

[rissson]

Probably caused by https://github.com/goauthentik/authentik/pull/7410. Should we fix this in authentik if we can?

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 85.57%. Comparing base (ecac913) to head (a3cb1ce).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #517 +/- ## ======================================= Coverage 85.57% 85.57% ======================================= Files 82 82 Lines 8075 8075 ======================================= Hits 6910 6910 Misses 756 756 Partials 409 409 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.