Update babel plugin to use runtime from react/compiler-runtime (#2918)

This uses the compiler runtime from `react/compiler-runtime` by default unless `compilerRuntime` is specifified in the Babel options which then imports the runtime from there. The `useMemoCache` hook is now named `c` in accordance with https://github.com/facebook/react/commit/4508873393058e86bed308b56e49ec883ece59d1

Unfortunately, I couldn't figure out how to import `react@beta` which already has that import as various react verstions were conflicting. If someone can figure this out it'd be fantastic. As a result, I had to update the default for the test runner to default the `compilerRuntime` option to `react` to preserve the previous behavior to import from `react`. Once upgraded to React 19, we should be able to remove that override.