Applying patch

Closes #3274049

core/modules/field/tests/src/Kernel/Migrate/d6/MigrateFieldFormatterSettingsTest.php

@@ -121,6 +121,7 @@ public function testEntityDisplaySettings() {
       'url_plain' => TRUE,
       'rel' => '0',
       'target' => '0',
+      'external_target' => '',
     ];
     $component = $display->getComponent('field_test_link');
     $this->assertSame($expected, $component);