fix: graphQLErrors in Error Link if networkError.result is an empty string

[PaLy]

Checklist:

• If this PR contains changes to the library itself (not necessary for e.g. docs updates), please include a changeset (see CONTRIBUTING.md)
• If this PR is a new feature, please reference an issue where a consensus about the design was reached (not necessary for small changes)
• Make sure all of the significant new logic is covered by tests

[apollo-cla]

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🦋 Changeset detected

Latest commit: 76eeb3e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

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@apollo/client	Patch

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[jerelmiller]

So sorry for the long wait on this PR! I've been meaning to look at this for a while and it slipped down my list, so apologies.

This looks great! I'll get the one suggestion committed, but I'll get this in the next patch release 🙂

[jerelmiller]

🎉