fix: fix export_headers_result with get_full_key

lib/tallty_import_export/export.rb

@@ -193,14 +193,18 @@ module TalltyImportExport
       records
     end
 
+    def get_full_key header
+      [header.with_indifferent_access[:json], header.with_indifferent_access[:key]].compact.join('.')
+    end
+
     def export_headers_result(**options)
       if @headers.present? && @group_key.blank?
-        headers_hash = @headers.to_h { |header| [header.with_indifferent_access[:key], header] }.with_indifferent_access
+        headers_hash = @headers.to_h { |header| [get_full_key(header), header] }.with_indifferent_access
         export_headers(**options.symbolize_keys).select do |_header|
-          _header.with_indifferent_access[:key].to_s.in?(headers_hash.keys)
+          get_full_key(_header).to_s.in?(headers_hash.keys)
         end.map do |_header|
           _header = _header.with_indifferent_access
-          _header.merge(headers_hash[_header[:key]].delete_if { |_k, v| v.blank? })
+          _header.merge(headers_hash[get_full_key(_header)].delete_if { |_k, v| v.blank? })
         end
       else
         @headers = export_headers(**options.symbolize_keys)