feat: Add reasoning item handling to skip non-message content

[ygbingo]

Summary

This PR aims to resolve #1164. In issue #1164, the problem [describe the problem briefly] was reported. This PR provides a solution by [explain the main changes you made to solve the problem].

Test plan

To ensure the effectiveness of the changes, the following test plan was implemented:

1. Unit tests: New unit tests were added to cover the modified functions and classes. These tests verify the correct behavior of the code under different input scenarios.
2. Integration tests: Integration tests were run to ensure that the changes do not break the existing functionality of the SDK. The full test suite was executed, and all tests passed successfully.
3. Manual testing: Manual testing was also performed to validate the changes in a real-world scenario. The [describe the specific operations in manual testing] was tested, and the results were as expected.

Checks

• I've added new tests (if relevant)
• I've added/updated the relevant documentation
• I've run make lint and make format
• I've made sure tests pass

Additional notes

If there are any other relevant details or considerations, such as potential impacts on other parts of the codebase, limitations of the solution, or future improvements, please mention them here.

[dotmobo]

+1

Would be cool to get the <think> content somehow.
But if this fix stops the whole message from blowing up, that’s already a win.

[seratch]

LGTM