fix: handle multiple tool calls in Mistral streaming responses

[siddhantwaghjale]

Description

This PR fixes a bug in the Mistral agentic implementation where only 1 tool call was reported to the agent instead of streaming multiple tool calls. The issue occurred because tool events were being processed immediately as received, but Mistral streams them out of order with all stop events reported together at the end. The fix accumulates tool call deltas and processes them in the correct sequence after stream completion, allowing Mistral to successfully stream multiple tool calls at once.

Related Issues

#374

Documentation PR

Type of Change

Bug fix

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

Note

• I tested with running hatch test and also ran hatch test tests-integ/test_model_mistral.py, both passed succesfully.
• However, while running hatch run test-integ, it's failing even with Mistral. But as the above hatch test tests-integ/test_model_mistral.py passed, I have created the PR

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

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[siddhantwaghjale]

@pgrayy can you confirm on the Note in the testing that I have added that it's not an issue