[BUG] Inconsistent qnode return behavior for list and tuple

[albi3ro]

Expected behavior

I would expect identical behavior for both lists or tuples.

Actual behavior

If we return a measurement process in a list, we add back in a dimension. But if the measurement process is in a tuple, we do not add a tuple dimension back in.

Additional information

No response

Source code

@qml.qnode(qml.device('default.qubit'))
def circuit(t):
    return t([qml.expval(qml.Z(0))])
>>> circuit(tuple)
1.0
>>> circuit(list)
[1.0]

Existing GitHub issues

• I have searched existing GitHub issues to make sure the issue does not already exist.