Describe the bug
A clear and concise description of what the bug is.

In the function_schema method of the OpenAI Agents SDK, the following line:

description=description_override or doc_info.description if doc_info else None

does not honor description_override when use_docstring_info=False. This happens because of operator precedence in Python. Without parentheses, the expression is interpreted as:

description=(description_override or doc_info.description) if doc_info else None

So when doc_info is None, even if description_override is set, it falls back to None

Debug information
Python version (e.g. Python 3.10)
Repro steps

from agents.function_schema import function_schema

def my_func():
    pass

schema = function_schema(
    my_func,
    description_override ="CustomDescription",
    use_docstring_info=False
)

print(schema.description) # Expected: "CustomDescription", Actual: None

Expected behavior

Even when use_docstring_info=False, if description_override is provided, it should be used for description.

Suggested Fix:
Update this line:
description=description_override or doc_info.description if doc_info else None
To this (with parentheses to enforce correct evaluation):
description=description_override or (doc_info.description if doc_info else None)