…che#22437)

- Reverts apache#20337
- Addresses concerns raised in
apache#22415
- Closes apache#22415

`ExecutionPlan::apply_expressions()` was added in apache#20337 with no default
implementation, forcing every custom `ExecutionPlan`, `FileSource`, and
`DataSource` implementor to add the method as part of upgrading to
DataFusion 54.

As discussed on apache#22415, per @LiaCastaneda and @adriangb the method is
not yet called from anywhere in DataFusion and the originally intended
use (dynamic-filter discovery/serialization for distributed scenarios)
is blocked on other in-progress work (apache#20009, apache#21350).

The combined effect on downstream users is a required code change with
no immediate benefit, and ambiguity about what a "correct"
implementation even means today (e.g. is returning
`Ok(TreeNodeRecursion::Continue)` is safe right now but becomes
incorrect as soon as the method starts being used by an optimizer pass?.

The plan agreed in the discussion is to remove the API from the 54.0
release and re-add it together with the concrete consumer that needs it.
cc @adriangb @LiaCastaneda @milenkovicm.

`git revert -m 1` of the merge commit, with the following manual
conflict resolutions and follow-ups:

By CI

Yes -- this removes the new public API:

- `ExecutionPlan::apply_expressions`
- `FileSource::apply_expressions`
- `DataSource::apply_expressions`

These were only added in 54 and are not yet released. Custom
implementors no longer need to implement these methods.