PLaplacianTests fail with Julia 1.7.3

The error is `ERROR: Scalar indexing on DebugArray is not allowed for performance reasons.` and it occurs at [this line](https://github.com/gridap/GridapDistributed.jl/blob/fac92506e1f5945c4ea12bf41f8ba6f9da382aa8/test/PLaplacianTests.jl#L13)

With Julia 1.9.3 it [runs sucessfully](https://github.com/gridap/GridapDistributed.jl/actions/runs/5947075300)

The reason for this behavior is the change in the implementation of `copy!(dst::AbstractVector, src::AbstractVector)` which indexed `dst` directly in v1.7.3, see [here](https://github.com/JuliaLang/julia/blob/742b9abb4dd4621b667ec5bb3434b8b3602f96fd/base/abstractarray.jl#L869), whereas it calls `copyto!` in v1.9.3, see [here](https://github.com/JuliaLang/julia/blob/bed2cd540a11544ed4be381d471bbf590f0b745e/base/abstractarray.jl#L924C57-L924C57)

Possible solutions I see:
1. increase compat
2. implement copy! for `DebugArray` and `MPIArray` in PartitionedArrays.jl
3. eliminate [this overload](https://github.com/gridap/GridapDistributed.jl/blob/fac92506e1f5945c4ea12bf41f8ba6f9da382aa8/test/PLaplacianTests.jl#L11C6-L11C6) which is not required after the [this commit](https://github.com/fverdugo/PartitionedArrays.jl/commit/965a2b97c3e5cf1f27d7c45db0870b137add58b4) to PartitionedArrays.jl (although the test will fail with previous releases). I verified that `copy(a::PSparseMatrix)` and `copy!(b::PSparseMatrix,a::PSparseMatrix)` work with latest PartitonedArrays.jl.

@fverdugo , @amartinhuertas , @JordiManyer any thoughts?