Python: allow openapi runner to use a custom client

[moonbox3]

Motivation and Context

A custom client was used to get the openapi spec but it wasn't passed down into the openapi runner.

Description

Pass the custom client into the open api runner if desired. Fix param parsing and samples.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[markwallace-microsoft]

Python 3.10 Test Coverage Report •

File	Stmts	Miss	Cover	Missing
semantic_kernel/connectors/openapi_plugin
openapi_function_execution_parameters.py	23	1	96%	33
openapi_manager.py	141	15	89%	15, 61–74, 104, 145, 150, 280, 350–363
TOTAL	5876	934	84%

Python 3.10 Unit Test Overview

Tests	Skipped	Failures	Errors	Time
1287	1 💤	0 ❌	0 🔥	14.858s ⏱️