Return successful `retcode` on `MaxIters` for `OptimizationSolution`

[Vaibhavdixit02]

For global, stochastic gradient etc maxiters is used as the stopping criteria

[ChrisRackauckas]

This is not the solution. The solution is to just correctly throw Success if that's what the return code is supposed to be. MaxIters is defined as a non-converged early max iterations return, not a successful return.