[StubGen] Fix optional vectors (#323) (#324)

[Karthick-Somasundaresan]

This is a backport from R4_4
It addresses an issue where a method's parameter is an optionalType and is empty; IsSet returns true.

[Copilot]

🔵 Needs a closer look

Changes affect core RPC stub/proxy code generation behavior and could have broad downstream compilation/runtime impact that warrants final human verification.

Pull request overview

This PR updates the ProxyStubGenerator’s code generation for OptionalType<std::vector<...>> parameters to correctly construct/populate vectors when optional values are present, and to reset optionals when absent, avoiding stale data across calls.

Changes:

• In stub-side input deserialization, populate optional vectors via a temporary vector object and move-assign into the optional wrapper.
• In proxy-side output deserialization, read vectors into either the target vector (clearing first) or a temporary vector for optionals, then move-assign.
• When an optional value is not present on the wire (boolean false), explicitly reset the optional parameter to its default-constructed state.

File summaries

File	Description
ProxyStubGenerator/StubGenerator.py	Fixes generation logic for optional dynamic arrays (vectors) during read/assignment in both stub and proxy paths, including resetting absent optionals.

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 0
• Review effort level: Lite

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