Opening netcdf file without using NetCDF gives confusing error

When I try to open a netcdf file with Cube without loading the NetCDF package before hand this fails with a confusing error.
I think, we can catch this earlier and give a more informative error message.

julia> wcormedian3 = Cube("data/cubes/s1cube_jurua_vh_smallchunks_wcor_median3.nc")ERROR: ArgumentError: Path data/cubes/s1cube_jurua_vh_smallchunks_wcor_median3.nc is not a directory.
Stacktrace:
  [1] storefromstring(s::String, create::Bool)
    @ Zarr ~/.julia/packages/Zarr/2V5d9/src/ZGroup.jl:103
  [2] zopen(s::String, mode::String; kwargs::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ Zarr ~/.julia/packages/Zarr/2V5d9/src/ZGroup.jl:91
  [3] zopen (repeats 2 times)
    @ ~/.julia/packages/Zarr/2V5d9/src/ZGroup.jl:91 [inlined]
  [4] YAXArrayBase.ZarrDataset(g::String)
    @ YAXArrayBase ~/.julia/packages/YAXArrayBase/OgYsV/src/datasets/zarr.jl:7
  [5] to_dataset(T::Type{YAXArrayBase.ZarrDataset}, g::String)
    @ YAXArrayBase ~/.julia/packages/YAXArrayBase/OgYsV/src/datasets/datasetinterface.jl:76
  [6] to_dataset(g::String; driver::Symbol)
    @ YAXArrayBase ~/.julia/packages/YAXArrayBase/OgYsV/src/datasets/datasetinterface.jl:72
  [7] to_dataset(g::String; driver::Symbol)
    @ YAXArrayBase ~/.julia/packages/YAXArrayBase/OgYsV/src/datasets/datasetinterface.jl:70
  [8] open_dataset(g::String; driver::Symbol)
    @ YAXArrays.Datasets ~/.julia/dev/YAXArrays/src/DatasetAPI/Datasets.jl:173
  [9] open_dataset
    @ ~/.julia/dev/YAXArrays/src/DatasetAPI/Datasets.jl:173 [inlined]
 [10] #Cube#79
    @ ~/.julia/dev/YAXArrays/src/DatasetAPI/Datasets.jl:415 [inlined]
 [11] Cube(s::String)
    @ YAXArrays.Datasets ~/.julia/dev/YAXArrays/src/DatasetAPI/Datasets.jl:415
 [12] top-level scope
    @ REPL[185]:1

Start at YAXArrays/src/DatasetAPI/Datasets.jl, especially open_dataset and Cube, and trace how a .nc path is handled when the NetCDF package has not been loaded. Check the existing dataset-opening tests, if present, and make the failure identify the missing NetCDF support instead of reporting that the path is not a directory.