[eslint-plugin-react-compiler] Fix type error with recommended config (#32666)

## Summary In the recommended configuration for `eslint-plugin-react-compiler`, i.e. `reactCompiler.configs.recommended`, the rule is typed as `string` rather than `eslint.Linter.RuleEntry` or anything assignable thereto, which results in the following type error if you type check your eslint configuration: ``` Property ''react-compiler/react-compiler'' is incompatible with index signature. Type 'string' is not assignable to type 'RuleEntry | undefined'. ``` Simply adding a const assertion fixes the error. ## How did you test this change? I emitted declarations for the module and confirmed that the rule is now typed as the string literal `'error'`