fix: Allow none structured output context in tool executors

[mkmeral]

Description

Make structured_output_context optional in tool executors. This is causing a bug for bidirectional streaming tool executions as they do not provide this context.

This param is already nullable in some places, and not nullable in others. This will make it consistent

Related Issues

Documentation PR

Type of Change

Bug fix

Testing

How have you tested the change? Verify that the changes do not break functionality or introduce warnings in consuming repositories: agents-docs, agents-tools, agents-cli

• I ran hatch run prepare

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

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Codecov Report

✅ All modified and coverable lines are covered by tests.

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