Handle zip imports regression

[ashfame]

Related issues

• Fixes https://github.com/Automattic/dotcom-forge/issues/10369

Proposed Changes

• Show a specific error to the user about this issue, and suggesting them to re-package the zip archive
• Change importBackup() and importSite() to not return undefined and just throw

Before	After

Testing Instructions

• Try importing a zip file which has absolute paths in it
• Before: Error would show as in the linked issue
• After: Specific error shown

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[fredrikekelund]

LGTM 👍 Given our current circumstance, the PR is an improvement, it tests well and the code looks good.

However… If many other unzip implementations (including the built-in tools on macOS and Windows) don't have a problem with leading slashes, I would strongly argue that Studio shouldn't either. I understand the argument that the spec makes about security, but my response would simply be: "let's automatically fix those filenames instead of outright rejecting the ZIP file". @ashfame, do you know of a way to do this with yauzl, or should we consider looking into replacement libraries for upcoming versions of Studio?

[ashfame]

@fredrikekelund Yep, I agree in principle of not leaving users hanging. Please see this comment where I laid down my thoughts on approaching this. I believe we need a archive handler abstraction that contains all this logic. We can continue that discussion there and figure out future next steps and let this PR be merged.

[sentry]

Suspect Issues

This pull request was deployed and Sentry observed the following issues:

• ‼️ Error: No suitable importer found for the provided backup contents <anonymous>(main/studio/./src/lib/import-export... View Issue
• ‼️ Error: No suitable backup handler found for the provided backup file <anonymous>(main/studio/./src/lib/import-export... View Issue

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[fredrikekelund]

All good with the Sentry error, it's expected 👍