test: add failing test for an aggregate of a calculation

[ahey]

An error occurs at compile time when an aggregate of a calculation is defined:

== Compilation error in file test/support/schema.ex == ** (MatchError) no match of right hand side value: {:error, "Must provide field type for max"}
    lib/resource/resource.ex:2278: AshGraphql.Resource.filterable?/2
    (elixir 1.15.4) lib/enum.ex:4265: Enum.filter_list/2
    (elixir 1.15.4) lib/enum.ex:4266: Enum.filter_list/2
    lib/resource/resource.ex:2229: AshGraphql.Resource.aggregate_filter_fields/2
    lib/resource/resource.ex:2195: AshGraphql.Resource.resource_filter_fields/2
    lib/resource/resource.ex:1159: AshGraphql.Resource.args/5
    lib/resource/resource.ex:425: anonymous fn/6 in AshGraphql.Resource.queries/5
    (elixir 1.15.4) lib/enum.ex:1693: Enum."-map/2-lists^map/1-1-"/2

[zachdaniel]

🚀 Thank you for your contribution! 🚀