fix: emit url.query_params as nested otel attributes

[Vadman97]

Summary

• Emit each URL query param as its own url.query_params.<key> OTel span attribute instead of one JSON-stringified blob, so the backend's hlog.FormatAttributes flattens them natively into a nested attribute map with no JSON parsing required.
• Repeated keys (?id=1&id=2) now become array-valued attributes; singletons stay as strings. The previous Object.fromEntries path silently dropped duplicates.
• New helper convertSearchParamsToOtelAttributes mirrors the existing convertHeadersToOtelAttributes pattern.

Test plan

• yarn turbo run test --filter highlight.run (413 tests pass; 7 new for the helper)
• yarn turbo run lint --filter highlight.run
• yarn format-check
• yarn turbo run build enforce-size --filter highlight.run --filter @launchdarkly/observability (brotli: 166 kB, under 256 kB limit)

🤖 Generated with Claude Code

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Note

Low Risk
Low risk: changes only how URL query params are represented on OTEL spans, with added unit tests; primary risk is minor downstream query/attribute-shape expectations.

Overview
Switches HTTP span query-param capture from a single JSON-stringified url.query_params attribute to per-param dotted attributes (e.g. url.query_params.foo), allowing backend attribute formatting to build nested maps without JSON parsing.

Adds convertSearchParamsToOtelAttributes to preserve repeated query keys as ordered arrays while keeping singletons as strings, and introduces a focused test suite covering duplicates, empty values, decoding, and custom prefixes.

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