test: retry temp folder removal for tests that spawn Electron

[erikian]

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• The changes are appropriately documented (if applicable).
• The changes have sufficient test coverage (if applicable).
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Summarize your changes:

When cleaning up temporary folders containing an Electron executable that is spawned by a test, fs.promises.rm can sometimes throw Error: EBUSY: resource busy or locked, unlink 'path\to\electron-app.exe' on Windows (see https://github.com/electron/forge/actions/runs/28900198935/job/85735026394#step:11:1731 and https://github.com/electron/forge/actions/runs/29090950003/job/86356018118#step:11:1763), failing the test.

This PR sets the maxRetries option for fs.promises.rm so we can handle this scenario more gracefully in the two tests where it can happen.