Returns or sets the data on a particular component inside the
user data map.
The user data is represented as a string for the sake of scripting
languages, but from C++ it is also possible to encode binary
data.
This is equivalent to retrieving a UserDataItem with UserDataMap.GetItem2 and then using
the UserDataItem.Value
property.
Note: This is the Python-compliant version of the UserDataMap.ItemValue. Since
Python does not support input parameters on properties,
UserDataMap.ItemValue will fail in Python.