add PhysicalProtoConverterExtension to PhysicalExtensionCodec #21056
Description
Is your feature request related to a problem or challenge?
Custom ExecutionPlan nodes that store PhysicalExpr fields (e.g., dynamic filter predicates pushed down during optimization) cannot participate in expression deduplication during serialization
This is because PhysicalExtensionCodec::try_encode and try_decode don't have access to the PhysicalProtoConverterExtension, so custom codecs must use serialize_physical_expr / parse_physical_expr directly, bypassing the deduplicating converter.
Describe the solution you'd like
The fix is to pass the PhysicalProtoConverterExtension reference through to try_encode and try_decode so custom codecs can use the converter.
Describe alternatives you've considered
No response
Additional context
No response