Remove DynamicPPL integration test (#1565)

Author: penelopeysm

.github/workflows/Downstream.yml

@@ -20,7 +20,6 @@ jobs:
         package:
           - {user: FluxML, repo: Flux.jl, group: All}
           - {user: FluxML, repo: NNlib.jl, group: All}
-          - {user: TuringLang, repo: DynamicPPL.jl, group: All}
           - {user: TuringLang, repo: DistributionsAD.jl, group: Zygote}
           - {user: SciML, repo: DiffEqFlux.jl, group: Layers}
           - {user: SciML, repo: DiffEqFlux.jl, group: BasicNeuralDE}