refactor: add try_to_proto / try_from_proto to DynamicFilterPhysicalExpr

[AnuragRaut08]

Which issue does this PR close?

Part of #22434

What changes are included?

Adds try_to_proto and try_from_proto to DynamicFilterPhysicalExpr
so it participates in the expression-local serialization pattern
introduced in #21929.

The centralized arms in to_proto.rs / from_proto.rs remain as
fallbacks for now. Cleanup of the pub-for-proto scaffolding
(from_parts, inner, original_children, remapped_children) can
follow in a separate PR once decode reads state directly.

Are these changes tested?

Yes — all three existing dynamic filter roundtrip tests pass:

• test_dynamic_filter_roundtrip_dedupe
• test_dynamic_filter_plan_roundtrip_dedupe
• test_dynamic_filter_expression_id_is_stable_between_serializations

Are there any user-facing changes?

No.

[AnuragRaut08]

All three existing dynamic filter roundtrip tests pass locally:

• test_dynamic_filter_roundtrip_dedupe
• test_dynamic_filter_plan_roundtrip_dedupe
• test_dynamic_filter_expression_id_is_stable_between_serializations

Happy to iterate quickly on any feedback. Also open to tackling the pub-for-proto scaffolding cleanup (from_parts, inner, original_children, remapped_children) as a follow-up PR once this lands, if that works for the maintainers.

[jayshrivastava]

Do you want to delete the public methods in this PR? I reviewed your current commit and it looks good.

Here's a commit removing the public methods you may want to cherry-pick.
52b1786

[jayshrivastava]

I don't think this path is being used. I think it needs to move to the impl PhysicalExpr block to override the default PhysicalExpr::try_to_proto implementation.

[adriangb]

@AnuragRaut08 are you able to move these methods and add tests?

[adriangb]

#22596 adds an expect_expr_variant! macro and a require_proto_field helper that together collapse the outer match and any non-expression "missing required field" ok_or_else to one line each. Could you rebase onto it and adopt them before final review?

[AnuragRaut08]

Thanks, I’m working through the rebase now.

After rebasing onto latest main, the module moved from dynamic_filters.rs to dynamic_filters/mod.rs, so I’m updating the implementation to follow the newer migrated try_to_proto / try_from_proto pattern used by the other physical expressions.

I’ve moved try_to_proto into the impl PhysicalExpr block and am now updating the decode path + tests. I’ll also rebase onto #22596 and adopt the new helpers before pushing the next revision.