Please describe the purpose of this pull request.
This pull request adds support for complex type annotations in the resolve_type function and expands the test suite to cover these new cases.

Improvements to type resolution:

• letta/functions/ast_parsers.py: Revised the resolve_type function to handle complex type annotations such as list, dict, and tuple.

Improvements to testing:

• tests/test_ast_parsing.py: Added multiple test cases to ensure correct coercion of arguments with complex type annotations, including list[int], dict[str, int], nested types like list[dict[str, int]], and handling of unsupported complex annotations.

How to test
poetry run pytest tests/test_ast_parsing.py

Have you tested this PR?
20 test cases passed.

Related issues or PRs
resolves #2430