[Pyhroff]

Part of #1600 (alongside #1599).

Summary

Fields, input fields, arguments, and Union (#1599) support lazy type references via dotted import strings or callables (lambda) to avoid circular imports across modules. However,
elay.Connection.Meta.node previously raised TypeError: issubclass() arg 1 must be a class when given a string or callable.

Changes

• Convert ConnectionOptions.node into a property backed by _node that resolves lazy references via get_type(self._node).
• Relax the Connection.init_subclass_with_meta node assertion to accept str and callables (inspect.isfunction / unctools.partial) in addition to concrete Graphene types and NonNull.
• Safely derive �ase_name when Connection is subclassed without a custom
  ame and
  ode is a string or callable.
• Add unit tests in graphene/relay/tests/test_connection.py covering string and lambda Meta.node definitions.