fix: output variable in PerturbOutput should not have a default

Author: AayushSabharwal

src/systems/analysis_points.jl

@@ -591,7 +591,6 @@ function apply_transformation(tf::PerturbOutput, sys::AbstractSystem)
         # add output variable, equation, default
         out_var, out_def = get_analysis_variable(
             ap_ivar, nameof(ap), get_iv(sys); perturb = false)
-        defs[out_var] = out_def
         push!(ap_sys_eqs, out_var ~ ap_ivar + wrap(new_var))
         push!(unks, out_var)