Fix permissioned pagination

[vecchp]

Fixes an error when trying to apply permission checks using the HasRetvalPerm extension on a paginated list.

TypeError: Cannot filter a query once a slice has been taken.

Types of Changes

• [ ] Core
• [X] Bugfix
• [ ] New feature
• [ ] Enhancement/optimization
• [ ] Documentation

Issues Fixed or Closed by This PR

Fix https://github.com/strawberry-graphql/strawberry-django/issues/471

Checklist

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [x] I have added tests to cover my changes.
• [x] I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[codecov-commenter]

Codecov Report

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

Comparison is base (94830a1) 87.90% compared to head (ccb8d77) 87.90%. Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #480 +/- ## ======================================= Coverage 87.90% 87.90% ======================================= Files 37 37 Lines 3167 3167 ======================================= Hits 2784 2784 Misses 383 383 ```

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