test: unbreak ARC and TrustRegions retcode tests

These were marked broken because retcodes always returned Failure.
Now that we properly use Manopt.has_converged, they correctly return
Success.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: SebastianM-C

lib/OptimizationManopt/test/runtests.jl

@@ -162,7 +162,7 @@ R2 = Euclidean(2)
 
         sol = OptimizationBase.solve(prob, opt)
         @test sol.objective < 0.1
-        @test SciMLBase.successful_retcode(sol) broken = true
+        @test SciMLBase.successful_retcode(sol)
     end
 
     @testset "TrustRegions" begin
@@ -178,7 +178,7 @@ R2 = Euclidean(2)
 
         sol = OptimizationBase.solve(prob, opt)
         @test sol.objective < 0.1
-        @test SciMLBase.successful_retcode(sol) broken = true
+        @test SciMLBase.successful_retcode(sol)
     end
 
     @testset "Custom constraints" begin