fix(openapi): explode object query parameters

[benclarkeio]

Link to Issue or Description of Change

1. Link to an existing issue (if applicable):

• Closes: Object-valued OpenAPI query parameters are serialized as dictionary strings #7233

Problem:

OpenAPI object-valued query parameters using the default form style with explode: true were passed to the HTTP client as dictionaries. The client encoded each dictionary as one string value instead of serializing its properties as separate query parameters.

Solution:

Read the query parameter's style and explode settings from the parsed operation. Expand dictionary properties into the request query mapping when form-style exploded serialization applies. Existing filtering continues to omit null values while preserving false and zero values.

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally.

82 passed, 17 warnings:

.venv/bin/pytest tests/unittests/tools/openapi_tool/openapi_spec_parser/test_rest_api_tool.py -q

Formatting, import ordering, and lint checks also pass for both changed files.

Manual End-to-End (E2E) Tests:

N/A. The regression test verifies the final request parameters at the HTTP client boundary.

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have manually tested my changes end-to-end.
• Any dependent changes have been merged and published in downstream modules.

Additional context

The implementation intentionally handles only the OpenAPI form plus explode: true object case described in the linked issue. Other serialization styles are unchanged.

[benclarkeio]

Superseded by #7208, which covers the default form/explode object case and the additional query serialization styles tracked in #7204. The regression test from this PR passes unchanged against #7208.