test: Pass private attribute raw paths to LDContext in contract tests

[keelerm84]

Summary

The contextComparison handler in the contract test service built LaunchDarkly::Reference objects and placed them in _meta.privateAttributes. But LDContext.create re-parses each element of that array as a reference string via Reference.create, which rejects any non-String/Symbol input. Every private attribute was therefore silently dropped, and context comparisons involving private attributes were never exercised -- both contexts were always compared with empty private-attribute sets.

The SDK's own LDContext equality is correct (order-independent set of references; literal names compare equal to the equivalent reference). The defect was isolated to the contract test service.

This passes the reference raw_path (a string) to LDContext.create instead of the Reference object. For a literal attribute name this is the escaped single-component form (e.g. /address/street -> /~1address~1street), which LDContext.create re-parses into the correct reference.

Verified locally by running the context type/compare suite from a local sdk-test-harness build against this service: all 16 comparison tests pass, including two negative cases where private attributes are the sole differentiator.

Note on ordering

The failing behavior was previously masked by a bug in the released test harness (a malformed privateAttributes JSON tag) that meant private attributes were never sent for the contextComparison command. That harness bug is fixed in launchdarkly/sdk-test-harness#391 (v2) and #392 (v3), which also add the negative tests that catch this. Until the harness fix is released, this SDK's contract-test CI (which downloads the released v2 harness) will not yet exercise the new cases.

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Note

Low Risk
Test-only change in the contract test service; no production SDK behavior is modified.

Overview
Fixes contract test contextComparison so _meta.privateAttributes is built the way LDContext.create expects.

The harness was putting LaunchDarkly::Reference instances into privateAttributes, but LDContext.create treats each entry as a reference string and re-parses it. Non-string values were dropped, so comparisons never exercised private attributes. The builder now passes each reference’s raw_path (including escaped literal paths from Reference.create_literal) so contexts are created with the intended private-attribute set.

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