feat: make feature flags available to @netlify/config

[lemusthelroy]

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Summary

By constructing our API client earlier, this PR feeds the feature flags into @netlify/config where the flags are required

Fixes #<replace_with_issue_number>
https://linear.app/netlify/issue/CT-1291/ensure-cli-passes-feature-flags-to-netlifyconfig

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[github-actions]

📊 Benchmark results

Comparing with 0f69e06

• Dependency count: 1,317 (no change)
• Package size: 480 MB ⬇️ 0.00% decrease vs. 0f69e06
• Number of ts-expect-error directives: 978 (no change)

[khendrikse]

Awesome!!

[eduardoboucas]

This is touching production code, so it shouldn't be a chore:. Can we please rename before merging?

[lemusthelroy]

I have pushed a commit on this by accident

[khendrikse]

I am loving this :)