Inconsistent type analysis in lambdas for redundant-expr

Bug Report
I found a weird issue related to redundant-expr that only happens when the code is defined as a lambda. The same code works fine when defined inside a regular function.

To Reproduce

from typing import Any

import pandas as pd

lambda val: {} if pd.isna(val) else val


def func(val: Any) -> Any:
    return {} if pd.isna(val) else val

Expected Behavior
None of the pd.isna calls are flagged as redundant
Actual Behavior

test_mypy.py:5: error: If condition is always false  [redundant-expr]
Found 1 error in 1 file (checked 1 source file)

Your Environment

• Mypy version used: mypy 1.15.0 (compiled: yes)
• Mypy command-line flags: mypy --enable-error-code redundant-expr test_mypy.py
• Mypy configuration options from mypy.ini (and other config files):
• Python version used: 3.12.9

Start by reproducing the report with the shown lambda and regular function using mypy --enable-error-code redundant-expr test_mypy.py. Trace how mypy analyzes lambda expressions and the redundant-expr condition. Done means equivalent lambda and function forms no longer produce the false redundant-condition diagnostic, with regression coverage for the example.