feat(ingestion): add feature flag for ingestion onboarding

[v-tarasevich-blitz-brain]

This PR adds a new feature flag: showIngestionOnboardingRedesign

[alwaysmeticulous]

✅ Meticulous spotted 0 visual differences across 998 screens tested: view results.

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_{Expected differences? Click here. Last updated for commit bcccb8c. This comment will update as new commits are pushed.}

[codecov]

Bundle Report

Changes will increase total bundle size by 69 bytes (0.0%) ⬆️. This is within the configured threshold ✅

Detailed changes

Bundle name	Size	Change
datahub-react-web-esm	28.7MB	69 bytes (0.0%) ⬆️

Affected Assets, Files, and Routes:

view changes for bundle: datahub-react-web-esm

Assets Changed:

Asset Name	Size Change	Total Size	Change (%)
assets/index-*.js	69 bytes	19.08MB	0.0%

Files in assets/index-*.js:

• ./src/appConfigContext.tsx → Total Size: 2.64kB

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

📢 Thoughts on this report? Let us know!

[chriscollins3456]

i have a suggestion on a different name but otherwise looks good! i think it makes sense to put version numbers in these flags in case we want another redesign around the same area in the future

[chriscollins3456]

maybe let's just call it ingestionOnboardingRedesignV1