Fix: workflow dependency task returns result content in result.message

[vria]

Description

Using dependencies in the workflow tool was unsuccessful because the results from dependency task were not available in the context of its dependent task. The issue was that the workflow tool did not properly extract the content from the AgentResult object returned by the dependency task.
This PR fixes it.

Related Issues

None

Documentation PR

None

Type of Change

Bug fix
Backward compatible

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
• My changes generate no new warnings
• Any dependent changes have been merged and published

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[cagataycali]

thank you for contributing!