Add checks for empty properties

- Some sample data might omit properties to save space or they could be missing for other reasons.

src/subset_tools.jl

@@ -319,6 +319,9 @@ function project_prop_on_subset!(
         return project_prop_on_subset!(prop, from_subset, to_subset)
     elseif from_subset.element[1].object[1].dimension >
            to_subset.element[1].object[1].dimension
+        if length(prop_arr) < 1
+            error("The property $(strip(repr(prop_arr))) is empty; there are no data available for any subset.")
+        end
         from_prop =
             get_prop_with_grid_subset_index(prop_arr, from_subset.identifier.index)
         if isnothing(from_prop)
@@ -371,6 +374,9 @@ function project_prop_on_subset!(
     value_field::Symbol=:values,
 ) where {T <: edge_profiles__prop_on_subset}
     from_prop = get_prop_with_grid_subset_index(prop_arr, from_subset.identifier.index)
+    if length(prop_arr) < 1
+        error("The property $(strip(repr(prop_arr))) is empty; there are no data available for any subset.")
+    end
     if isnothing(from_prop)
         error(
             "from_subset ($(from_subset.identifier.index)) not represented in the property yet",