Add backend_cpu dependency for aidge_onnx testing

.gitlab/ci/common/download.gitlab-ci.yml

@@ -95,12 +95,12 @@
     - set -x
     - >
       if [[ $CI_PROJECT_NAME == "aidge_backend_cpu"    ]] || \
-           [[ $CI_PROJECT_NAME == "aidge_onnx"         ]] || \
          [[ $CI_PROJECT_NAME == "aidge_backend_opencv" ]]; then
         DEPS_NAMES=("aidge_core")
       elif [[ $CI_PROJECT_NAME == "aidge_backend_cuda" ]] || \ 
            [[ $CI_PROJECT_NAME == "aidge_learning"     ]] || \
            [[ $CI_PROJECT_NAME == "aidge_export_cpp"   ]] || \
+           [[ $CI_PROJECT_NAME == "aidge_onnx"         ]] || \ # backend_cpu dependency only for test
            [[ $CI_PROJECT_NAME == "aidge_quantization" ]]; then
         DEPS_NAMES=("aidge_core" "aidge_backend_cpu")
       else