Remove intent Out

[certik]

Due to https://github.com/lfortran/lfortran/pull/7842#issuecomment-2993661103, the intent Out doesn't have an equivalent behavior in Python, since for structs with default values we would need to initialize them on function enter, which Python doesn't do. So the subset of Python can only do intent In (read only --- enforced by LPython) and intent InOut (the default in Python for non-primitive types). Primitive types must be intent In (effectively read only), we already do that.