fix: do not call flatten_equations in JumpSystem

Author: AayushSabharwal

src/systems/jumps/jumpsystem.jl

@@ -151,7 +151,6 @@ function JumpSystem(eqs, iv, unknowns, ps;
         kwargs...)
     name === nothing &&
         throw(ArgumentError("The `name` keyword must be provided. Please consider using the `@named` macro"))
-    eqs = flatten_equations(eqs)
     sysnames = nameof.(systems)
     if length(unique(sysnames)) != length(sysnames)
         throw(ArgumentError("System names must be unique."))