Fix code_widget_class for PW

[superstar54]

I used PwCodeModel, but got an error that there is no parallelization widget. Then I learned that I need to pass PwCodeResourceSetupWidget as the code_widget_class.

It would be good to make PwCodeResourceSetupWidget default code_widget_class for PwCodeModel.

[codecov[bot]]

Codecov Report

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

Project coverage is 68.05%. Comparing base (97915df) to head (e01976b). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #938 +/- ## ========================================== + Coverage 68.04% 68.05% +0.01% ========================================== Files 104 104 Lines 5793 5795 +2 ========================================== + Hits 3942 3944 +2 Misses 1851 1851 ``` | [Flag](https://app.codecov.io/gh/aiidalab/aiidalab-qe/pull/938/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidalab) | Coverage Δ | | |---|---|---| | [python-3.11](https://app.codecov.io/gh/aiidalab/aiidalab-qe/pull/938/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidalab) | `68.05% <100.00%> (+0.01%)` | :arrow_up: | | [python-3.9](https://app.codecov.io/gh/aiidalab/aiidalab-qe/pull/938/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidalab) | `68.06% <100.00%> (+0.01%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=aiidalab#carryforward-flags-in-the-pull-request-comment) to find out more.

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