refactor(types): remove dead catch-all clauses unreachable per success typing

lib/mv/membership/import/member_csv.ex

@@ -210,8 +210,6 @@ defmodule Mv.Membership.Import.MemberCSV do
     MapSet.member?(HeaderMapper.known_member_fields(), normalized)
   end
 
-  defp member_field?(_), do: false
-
   # Validates that row count doesn't exceed limit
   defp validate_row_count(rows, max_rows) do
     if length(rows) > max_rows do

lib/mv/membership/member_export.ex

@@ -522,6 +522,4 @@ defmodule Mv.Membership.MemberExport do
       other -> other
     end)
   end
-
-  defp normalize_computed_fields(_), do: []
 end