refactor: port Literal physical expr proto hooks

[officialasishkumar]

Which issue does this PR close?

• Closes Port Literal to use try_to_proto / try_from_proto #22427.

Rationale for this change

DataFusion is migrating built-in physical expressions to own their protobuf serialization and deserialization through the try_to_proto / try_from_proto hooks added in #21929. Literal still used the central physical expression proto match.

What changes are included in this PR?

This ports Literal to the per-expression proto hook pattern and updates physical expression decoding to delegate literal reconstruction to Literal::try_from_proto. The protobuf wire format is unchanged.

Are these changes tested?

Yes.

• cargo fmt --all -- --check
• cargo test -p datafusion-proto --test proto_integration cases::roundtrip_physical_plan::roundtrip_filter_with_not_and_in_list
• cargo test -p datafusion-proto --test proto_integration cases::roundtrip_physical_plan::roundtrip_hash_table_lookup_expr_to_lit
• cargo test -p datafusion-proto --test proto_integration cases::roundtrip_physical_plan::roundtrip_call_null_scalar_struct_dict
• cargo test -p datafusion-proto --test proto_integration cases::roundtrip_physical_plan::test_round_trip_human_display
• git diff --check

Are there any user-facing changes?

No. This is an internal serialization refactor with the same serialized representation.

[adriangb]

A single round trip unit test in a test mod like this one would be great:

datafusion/datafusion/physical-expr/src/expressions/like.rs

Lines 348 to 349 in cab69a1

	#[cfg(all(test, feature = "proto"))]
	mod proto_tests {

[adriangb]

@officialasishkumar please resolve conflicts 🙏🏻

[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?

[adriangb]

Thanks for the contribution @officialasishkumar . This was completed in #22636 so I'll close this PR.