dillon1000/react

[compiler] Allow ReactElement symbol to be configured when inlining jsx (#30996)

Based on https://github.com/facebook/react/pull/30995 ([rendered
diff](https://github.com/jackpope/react/compare/inline-jsx-2...jackpope:react:inline-jsx-3?expand=1))

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Some apps still use `react.element` symbols. Not only do we want to test
there but we also want to be able to upgrade those sites to
`react.transitional.element` without blocking on the compiler (we can
change the symbol feature flag and compiler config at the same time).

The compiler runtime uses `react.transitional.element`, so the snap
fixture will fail if we change the default here. However I confirmed
that commenting out the fixture entrypoint and running snap with
`react.element` will update the fixture symbols as expected.