fix(litellm): map LiteLLM context window errors to ContextWindowOverflowException

[Ratish1]

Description

Previously, when LiteLLM raised a context window related error , it wasn’t mapped to our standard ContextWindowOverflowException. This update fixes that by detecting these errors and raising ContextWindowOverflowException so that agents can handle input more reliably.

Key Changes

• Updated src/strands/models/litellm.py to catch LiteLLM client exceptions and raise ContextWindowOverflowException for context-window overflow messages
• Adjusted structured_output logic to ensure mapping occurs before unsupported model checks when relevant.
• Updated the test file tests/strands/models/test_litellm.py to patch supports_response_schema where needed, ensuring the test properly covers the exception mapping path.

Related Issues

Fixes #974

Documentation PR

N/A

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

• Ran pre-commit hooks and linters.
• Ran unit tests locally: pytest -q tests/strands/models/test_litellm.py
• 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

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