feat(ollama): add support for ollama thinking in stream invocations

[scippacercola]

Description

Add support for Ollama Thinking.

references:

• https://ollama.com/blog/thinking
• https://docs.ollama.com/capabilities/thinking

Type of Change

New feature

Testing

The change is very limited and compliant to what I could see in other model implementation.
I create specific tests and perform hatch run prepare.

Could not check in consuming repositories but I don't foresee any reason to break consumers, since there are no any changes in the interface.

Could not perform automatic integration tests, but I performed test in my environment.

Could not update documentation since couldn't find any specific place to update.

• 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

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.