test: import NonlinearSolve.jl in downstream tests

Author: AayushSabharwal

test/downstream/linearization_dd.jl

@@ -7,6 +7,7 @@ using ModelingToolkitStandardLibrary.Blocks
 using ModelingToolkitStandardLibrary.Mechanical.MultiBody2D
 using ModelingToolkitStandardLibrary.Mechanical.TranslationalPosition
 using Test
+import NonlinearSolve
 
 using ControlSystemsMTK
 using ControlSystemsMTK.ControlSystemsBase: sminreal, minreal, poles

test/downstream/test_disturbance_model.jl

@@ -6,6 +6,7 @@ analysis-point specific method for `generate_control_function`.
 using ModelingToolkit, OrdinaryDiffEqTsit5, LinearAlgebra, Test
 using ModelingToolkitStandardLibrary.Mechanical.Rotational
 using ModelingToolkitStandardLibrary.Blocks
+import NonlinearSolve
 using ModelingToolkit: connect
 # using Plots