fix: linearized operands in physical binaryexpr protobuf to avoid recursion limit

[haohuaijin]

Which issue does this PR close?

• part of Decode proto: DecodeError: recursion limit reached #18602.

Rationale for this change

When a SQL query contains many filter conditions (e.g., 40+ AND/OR clauses in a WHERE), serializing the physical plan to protobuf and deserializing it fails with DecodeError: recursion limit reached. This is because prost has a default recursion limit of 100, and each BinaryExpr nesting consumes ~2 levels of protobuf recursion depth, so a chain of ~50 AND conditions exceeds the limit.

What changes are included in this PR?

Applied the same linearization approach that logical expressions already use. Instead of encoding a chain of same-operator binary expressions as a deeply nested tree, we flatten it into a flat operands list:

Before (nested, O(n) recursion depth):

BinaryExpr(AND) { l: BinaryExpr(AND) { l: BinaryExpr(AND) { l: a, r: b }, r: c }, r: d }

After (flat, O(1) recursion depth for the chain):

BinaryExpr(AND) { operands: [a, b, c, d] }

Are these changes tested?

yes, add some test case

Are there any user-facing changes?