Fix rubocop offences

https://buildkite.com/rails/rails/builds/112861#0192a2dc-39ea-4860-bcd2-f67dab8d09d3/1225-1229

Author: kamipo

railties/test/generators/authentication_generator_test.rb

@@ -107,23 +107,22 @@ def test_model_test_is_skipped_if_test_framework_is_given
   end
 
   private
-
-  def run_generator_instance
-    commands = []
-    command_stub ||= -> (command, *args) { commands << [command, *args] }
-
-    @rails_commands = []
-    @rails_command_stub ||= -> (command, *_) { @rails_commands << command }
-
-    content = nil
-    generator.stub(:execute_command, command_stub) do
-      generator.stub(:rails_command, @rails_command_stub) do
-        content = super
+    def run_generator_instance
+      commands = []
+      command_stub ||= -> (command, *args) { commands << [command, *args] }
+
+      @rails_commands = []
+      @rails_command_stub ||= -> (command, *_) { @rails_commands << command }
+
+      content = nil
+      generator.stub(:execute_command, command_stub) do
+        generator.stub(:rails_command, @rails_command_stub) do
+          content = super
+        end
       end
-    end
 
-    @bundle_commands = commands.filter { |command, _| command == :bundle }
+      @bundle_commands = commands.filter { |command, _| command == :bundle }
 
-    content
-  end
+      content
+    end
 end