language_models: Add thinking support for ollama (#31665)

This PR updates how we handle Ollama responses, leveraging the new
[v0.9.0](https://github.com/ollama/ollama/releases/tag/v0.9.0) release.
Previously, thinking text was embedded within the model's main content,
leading to it appearing directly in the agent's response. Now, thinking
content is provided as a separate parameter, allowing us to display it
correctly within the agent panel, similar to other providers. I have
tested this with qwen3:8b and works nicely. ~~We can release this once
the ollama is release is stable.~~ It's released now as stable.

<img width="433" alt="image"
src="https://github.com/user-attachments/assets/2983ef06-6679-4033-82c2-231ea9cd6434"
/>


Release Notes:

- Add thinking support for ollama

---------

Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>

crates/agent_settings/src/agent_settings.rs

@@ -372,6 +372,7 @@ impl AgentSettingsContent {
                                 None,
                                 None,
                                 Some(language_model.supports_tools()),
+                                None,
                             )),
                             api_url,
                         });