Consider deprecate or remove some physical expr helper functions

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

I find some old helper functions are no longer needed or recommended for use.

For example, `physical_exprs_contains` only has one reference from `get_aggregate_expr_req` and may be replaced with an `IndexSet`. `physical_exprs_bag_equal` only has one reference from `InListExpr`.

https://github.com/apache/datafusion/blob/bb1b55cfba27a0b3090aa114ff7e05be1a039252/datafusion/physical-expr/src/physical_expr.rs#L54-L63

And `physical_exprs_equal` is not necessary to exist

https://github.com/apache/datafusion/blob/bb1b55cfba27a0b3090aa114ff7e05be1a039252/datafusion/physical-expr/src/physical_expr.rs#L65-L71

### Describe the solution you'd like

- Most of them are like substitutes before we have https://github.com/apache/datafusion/pull/13005, and are either not necessary or may indicate something can be improved at present.

Would like to raise this ticket as a discussion to remove or deprecate them.

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Review the helper functions in datafusion/physical-expr/src/physical_expr.rs, especially physical_exprs_contains, physical_exprs_bag_equal, and physical_exprs_equal. Trace their mentioned uses in get_aggregate_expr_req and InListExpr, and consider the context of pull request 13005; done means reaching a decision on which helpers can be removed or deprecated.

Written by the indexing model from the issue text.