get_property_set(ps_name) only returns the first match

[rahul-sundaresan]

In apstra GUI, you can create multiple property sets with the same name and keys with no errors. Not sure if this is by design since configlets enforce the unique name rule

But if this is the case, then the get_property_set(ps_name) only returns the first match.

This is not a big deal since the chances of that happening are very slim, but just documenting this behavior.

Can I add a fix for this in #42 ?