Support volatile functions and scalar variables in ListingTable partition pruning

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

Currently `ListingTable` partition prunning doesn't support volatile functions and scalar variables, like `now()` or `$var`, which is checked at https://github.com/apache/datafusion/blob/4b8c1d9d6b4eb7ebb2876abbed911055b4badfad/datafusion/catalog-listing/src/helpers.rs#L51-L118

### Describe the solution you'd like

Volatile functions and scalar variables being supported in `ListingTable` partition pruning

### Describe alternatives you've considered

_No response_

### Additional context

Suggested by @comphead at [#21679](https://www.github.com/apache/datafusion/pull/21679#discussion_r3094909808)

Start with the partition-pruning checks in datafusion/catalog-listing/src/helpers.rs, especially lines 51-118, then trace how ListingTable supplies expressions for pruning. Verify the behavior for volatile functions such as now() and scalar variables such as $var; done means both are supported without preventing correct partition pruning.

Written by the indexing model from the issue text.