fix(ollama): preserve tools across agent loop turns (#13254)

[maoxin1234]

Description

Fixes #13254. In core/llm/llms/Ollama.ts, options.tools was only forwarded if ollamaMessages.at(-1)?.role === 'user'. In multi-turn tool calling and agent loops, subsequent turns have assistant or tool message histories, causing Ollama to drop the tools definitions mid-loop.

This PR removes the unnecessary restriction, ensuring options.tools remains available throughout multi-turn tool interactions.

Checklist

• I've read the contributing guide
• The relevant docs, if any, have been updated or created
• The relevant tests, if any, have been updated or created

Tests

• Added unit test in core/llm/llms/Ollama.test.ts verifying tools persistence when the last message is a tool response.
• Executed �un test core/llm/llms/Ollama.test.ts (all 8 tests passing).

[github-actions]

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[maoxin1234]

I have read the CLA Document and I hereby sign the CLA