Fix crash in refactoring checker when calling bound lambda
Fixes:
```
File "sources/pylint/pylint/checkers/refactoring/refactoring_checker.py", line 2094, in _is_function_def_never_returning
and node.returns
^^^^^^^^^^^^
File "sources/pylint/.venv/lib/python3.11/site-packages/astroid/bases.py", line 138, in __getattr__
return getattr(self._proxied, name)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'Lambda' object has no attribute 'returns'
```
Crash is reproducible if you have something like this:
```python
class C:
eq = lambda self, y: self == y
```
As a workaround, use a normal function instead of a lambda.
Closes #9865
(cherry picked from commit b78deb6140799549ae5f2afc9cb5bc8c1afda5cc)
3 files changed
