Add support for dual_ftol_rel parameter in NLopt

Fixes #922 - Added handling for the dual_ftol_rel parameter which is
used by MMA/CCSA algorithms in NLopt to control the dual optimization
subproblem tolerance.

Previously, passing dual_ftol_rel would throw:
```
ERROR: UndefVarError: `dual_ftol_rel\!` not defined
```

Now the parameter is properly handled using NLopt.nlopt_set_param()
since it's not a direct setter function but a named parameter.

Changes:
- Added special case handling for dual_ftol_rel in __map_optimizer_args\!
- Uses NLopt.nlopt_set_param(opt, "dual_ftol_rel", value) instead of
  trying to call a non-existent dual_ftol_rel\! function

This enables users to control the dual problem tolerance for faster
convergence in high-dimensional problems with CCSA/MMA algorithms.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ChrisRackauckas

lib/OptimizationNLopt/src/OptimizationNLopt.jl

@@ -93,7 +93,12 @@ function __map_optimizer_args!(cache::OptimizationCache, opt::NLopt.Opt;
     # add optimiser options from kwargs
     for j in kwargs
         if j.first != :cons_tol
-            eval(Meta.parse("NLopt." * string(j.first) * "!"))(opt, j.second)
+            # Handle special parameters that use nlopt_set_param
+            if j.first == :dual_ftol_rel
+                NLopt.nlopt_set_param(opt, "dual_ftol_rel", j.second)
+            else
+                eval(Meta.parse("NLopt." * string(j.first) * "!"))(opt, j.second)
+            end
         end
     end