Use foldhash hasher

### Is your feature request related to a problem or challenge?

Hashbrown now switched to use foldhasher (https://github.com/orlp/foldhash). We should benchmark this and switch if it makes sense to.

### Describe the solution you'd like

_No response_

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Start by locating DataFusion's hashbrown usage and benchmark entry points, then review how Hashbrown's foldhash change applies to those paths. Compare current hashing performance with foldhash and document whether the results justify switching; done means the benchmark evidence supports a clear decision and the relevant usage is updated if appropriate.

Written by the indexing model from the issue text.