[WIP] Migrate fuchsia_archive.gni to the GN SDK

[mattcarrollcode]

Description

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[cbracken]

Is this still WIP? Should we close this until it's ready?

[fluttergithubbot]

This pull request is not suitable for automatic merging in its current state.

• Please get at least one approved review before re-applying this label. Reviewers: If you left a comment approving, please use the "approve" review action instead.
• The status or check suite Linux Host Engine has failed. Please fix the issues identified (or deflake) before re-applying this label.
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[cbracken]

Closing for the moment to clear out the stale review queue -- but please send a new patch when you're ready!