Resource.copy() does not work

[jacobtylerwalls]

Not urgent as the button is disabled since #8445, but should be solved with #8352

>>> ri
>>> ri = ResourceInstance(pk='af792d07-e8a7-4f60-929e-591d2dfc4579')
>>> ri.refresh_from_db()
>>> ri.graph
<GraphModel: Instrument>
>>> r = Resource(ri.pk)
>>> r.graph = ri.graph
>>> r.copy()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/web_root/arches/arches/app/models/resource.py", line 752, in copy
    new_resource.save(context="copy")
  File "/web_root/arches/arches/app/models/resource.py", line 249, in save
    self.index(context)
  File "/web_root/arches/arches/app/models/resource.py", line 337, in index
    document, terms = self.get_documents_to_index(datatype_factory=datatype_factory, node_datatypes=node_datatypes, context=context)
  File "/web_root/arches/arches/app/models/resource.py", line 383, in get_documents_to_index
    context["language"] = lang[0]
TypeError: 'str' object does not support item assignment

[jacobtylerwalls]

In 8.0, this method will also need to be updated to no longer set nodegroup =.