fix(eject): preserve React 17 automatic JSX runtime after eject (#9953, #17109)

[DipakHalkude]

…fter eject

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[DipakHalkude]

Problem:
After eject, apps on React 17+ can hit “ReferenceError: React is not defined” when using the automatic JSX transform because the ejected Babel config didn’t explicitly set the JSX runtime, effectively falling back to classic.
Change: Update packages/react-scripts/scripts/eject.js to detect react/jsx-runtime and write Babel presets in package.json as:
["react-app", { "runtime": "automatic" | "classic" }]
Mirrors the runtime detection already used in webpack and jest configs.

Impact:
Ejected apps with React 17+ continue to work without import React. No change for React < 17 or when DISABLE_NEW_JSX_TRANSFORM=true.

Files
packages/react-scripts/scripts/eject.js

[DipakHalkude]

I signed the CLA

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