Allow SetUseSimTime to disable simulated time

[Old-Ding]

Summary

• compare the resulting use_sim_time value with the requested boolean instead of requiring it to be true
• preserve the existing failure path when the resulting value does not match the request
• extend the XML and YAML frontend test with native false values while retaining true substitution coverage

Testing

• reproduced the current RuntimeError after SetUseSimTime(False) had already set the parameter to false
• passed XML/YAML true and false parser-to-action execution probes using the real launch frontends and a fake node at the unavailable rclpy boundary
• ament_flake8 on both changed files
• ament_pep257 on both changed files
• ament_copyright on both changed files
• python -m py_compile on both changed files
• git diff --check

The repository-native frontend test was not run locally because this Windows environment does not have a compiled rclpy extension.

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