Fix Optimisers.jl wrapper on GPU

[blegat]

@dpo Would it make sense to move this into a package in JSO ?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.22%. Comparing base (fb407b2) to head (5613356).

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #85   +/-   ##
=======================================
  Coverage   92.22%   92.22%           
=======================================
  Files          25       25           
  Lines        3217     3217           
=======================================
  Hits         2967     2967           
  Misses        250      250           

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[dpo]

@blegat Sorry, move what exactly?

[blegat]

Sorry, this lacked context. In

ArrayDiff.jl/test/OptimisersSolver.jl

Lines 10 to 15 in c0bfb74

	mutable struct OptimisersSolver{R<:Optimisers.AbstractRule,V<:AbstractVector} <:
	SolverCore.AbstractOptimizationSolver
	rule::R
	x::V
	g::V
	end

there is a simple wrapper to use Optimisers.jl using the NLPModels interface. Using then NLPModelsJuMP.jl, it can also be used from JuMP.
This is jsut a file in the test here but it would be probably better to move it as a separate package or as a package extension of Optimisers.jl