Fix: don't put zipped multi-ROM games in a subdirectory

[codecov[bot]]

Codecov Report

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

Project coverage is 93.20%. Comparing base (860a9d2) to head (128742e).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1154 +/- ## ======================================= Coverage 93.20% 93.20% ======================================= Files 102 102 Lines 6373 6373 Branches 1516 1508 -8 ======================================= Hits 5940 5940 Misses 410 410 Partials 23 23 ```

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

[github-actions[bot]]

:test_tube: Branch testing instructions

This pull request can be tested locally with the following command:

npm exec --yes -- "github:emmercm/igir#emmercm/extension-correction-fix" [commands..] [options]

Comment generated by the Pull Request Commenter workflow.