fix: ignore browserslist file

[chrisbreiding]

• Closes 5.4.0 Regression: Webpack Compilation Error when browserslist is present in project root #8864

User facing changelog

• Fixed an issue where the presence of a browserslist file would cause file preprocessing to error.

PR Tasks

• N/A Have tests been added/updated? Wasn't able to create an e2e test that failed before this fix, due to the way that e2e are different from production Cypress
• Has the original issue or this PR been tagged with a release in ZenHub?
• N/A Has a PR for user-facing changes been opened in cypress-documentation?
• N/A Have API changes been updated in the type definitions?
• N/A Have new configuration options been added to the cypress.schema.json?

[cypress-bot]

Thanks for taking the time to open a PR!

• Create a Draft Pull Request if your PR is not ready for review. Mark the PR as Ready for Review when you're ready for a Cypress team member to review the PR.
• Become familiar with the Code Review Checklist for guidelines on coding standards and what needs to be done before a PR can be merged.

[bondar-artem]

So this fix was not released?