[TASK] update sys_language_uid in TCA & formatting

Configuration/TCA/tx_sgmail_domain_model_layout.php

@@ -64,21 +64,25 @@ $columns = [
 			],
 		],
 		'sys_language_uid' => [
-			'exclude' => true,
+			'exclude' => TRUE,
 			'label' => 'LLL:EXT:core/Resources/Private/Language/locallang_general.xlf:LGL.language',
 			'config' => [
 				'type' => 'select',
 				'renderType' => 'selectSingle',
+				'special' => 'languages',
 				'foreign_table' => 'sys_language',
 				'foreign_table_where' => 'ORDER BY sys_language.title',
 				'items' => [
-					['LLL:EXT:core/Resources/Private/Language/locallang_general.xlf:LGL.allLanguages', -1],
-					['LLL:EXT:core/Resources/Private/Language/locallang_general.xlf:LGL.default_value', 0]
+					[
+						'LLL:EXT:core/Resources/Private/Language/locallang_general.xlf:LGL.allLanguages',
+						-1,
+						'flags-multiple'
+					]
 				],
 				'default' => 0,
 				'fieldWizard' => [
 					'selectIcons' => [
-						'disabled' => false,
+						'disabled' => FALSE,
 					],
 				],
 			]

Configuration/TCA/tx_sgmail_domain_model_mail.php

@@ -193,7 +193,8 @@ $columns = [
 						'collapseAll' => TRUE
 					],
 					'maxitems' => 9999
-				])
+				]
+			)
 		]
 	]
 ];