refactor: parameter_dependencies is now called recursively

`subsys` might not have parameter dependencies, but subsystems of `subsys` might

Co-authored-by: Aayush Sabharwal <aayush.sabharwal@gmail.com>

Author: SebastianM-C

src/systems/abstractsystem.jl

@@ -996,8 +996,6 @@ function parameter_dependencies(sys::AbstractSystem)
     systems = get_systems(sys)
     isempty(systems) && return pdeps
     for subsys in systems
-        isnothing(get_parameter_dependencies(subsys)) && continue
-
         pdeps = merge(pdeps, namespace_parameter_dependencies(subsys))
     end
     # @info pdeps