[Diagnostic] remove tautalogical error message
In simplify, we were not using the provided function apply depth to
pass to resolve overload in all circumstances but setting a default
that did not apply when the function is provided as an argument.
By changing this to the given function apply depth, this corrects
behaviour in resolve overload and record overload to remove labels
when appropriate and thus not produce error messages with the same
function type appearing twice in conversion fixes.