Call export_xml_lettings_logs with nil if no year is given

lib/tasks/data_export.rake

@@ -13,7 +13,7 @@ namespace :core do
 
   desc "Export all data XMLs for import into Central Data System (CDS)"
   task :full_data_export_xml, %i[year] => :environment do |_task, args|
-    collection_year = args[:year].presence || false
+    collection_year = args[:year].presence
     storage_service = Storage::S3Service.new(PlatformHelper.is_paas? ? Configuration::PaasConfigurationService.new : Configuration::EnvConfigurationService.new, ENV["EXPORT_PAAS_INSTANCE"])
     export_service = Exports::LettingsLogExportService.new(storage_service)
 

spec/lib/tasks/data_export_spec.rb

@@ -32,7 +32,7 @@ describe "rake core:data_export", type: task do
 
     context "with all available years" do
       it "calls the export service" do
-        expect(export_service).to receive(:export_xml_lettings_logs).with(full_update: true, collection_year: false)
+        expect(export_service).to receive(:export_xml_lettings_logs).with(full_update: true, collection_year: nil)
 
         task.invoke
       end