cyipopt fails with load_solutions=False

[ZedongPeng]

Summary

cyipopt solver will fail when we set load_solution=False.

Steps to reproduce the issue

pyomo/pyomo/contrib/pynumero/interfaces/tests/test_external_pyomo_block.py

Lines 199 to 223 in 99dc0f1

	def test_solve_square(self):
	m = pyo.ConcreteModel()
	m.ex_block = ExternalGreyBoxBlock(concrete=True)
	block = m.ex_block
	m_ex = _make_external_model()
	input_vars = [m_ex.a, m_ex.b, m_ex.r, m_ex.x_out, m_ex.y_out]
	external_vars = [m_ex.x, m_ex.y]
	residual_cons = [m_ex.c_out_1, m_ex.c_out_2]
	external_cons = [m_ex.c_ex_1, m_ex.c_ex_2]
	ex_model = ExternalPyomoModel(
	input_vars, external_vars, residual_cons, external_cons
	)
	block.set_external_model(ex_model)
	_add_linking_constraints(m)
	m.a.fix(1)
	m.b.fix(2)
	m.r.fix(3)
	m.obj = pyo.Objective(expr=0)
	solver = pyo.SolverFactory("cyipopt")
	solver.solve(m)

Change line 223 to solver.solve(m,load_solutions=False)

Error Message

$ # Output message here, including entire stack trace, if available
======================================================================
ERROR: test_solve_square (__main__.TestExternalGreyBoxBlock)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/zedongpeng/Github/pyomo/pyomo/contrib/pynumero/interfaces/tests/test_external_pyomo_block.py", line 223, in test_solve_square
    solver.solve(m,load_solutions=False)
  File "/Users/zedongpeng/Github/pyomo/pyomo/contrib/pynumero/algorithms/solvers/cyipopt_solver.py", line 405, in solve
    sm = nlp.symbol_map
AttributeError: 'PyomoNLPWithGreyBoxBlocks' object has no attribute 'symbol_map'

Information on your system

Pyomo version: 6.6.2.dev0
Python version: 3.10.12
Operating system: macOS
How Pyomo was installed (PyPI, conda, source): source
Solver (if applicable): cyipopt

Additional information

[ZedongPeng]

Any suggestions or thoughts about this? @jsiirola