Remove meaningless and possibly wrong for attr.

The generated for attribute for input group labels was pretty much
always wrong. Instead of trying to make it correct just omit it.

src/View/Helper/FormHelper.php

@@ -1174,7 +1174,7 @@ protected function _magicOptions($fieldName, $options, $allowOverride) {
  * @return bool|string false or Generated label element
  */
 	protected function _getLabel($fieldName, $options) {
-		if (in_array($options['type'], ['hidden'])) {
+		if ($options['type'] === 'hidden') {
 			return false;
 		}
 
@@ -1233,6 +1233,9 @@ protected function _inputLabel($fieldName, $label, $options) {
 		$options += ['id' => null, 'input' => null, 'nestedInput' => false];
 
 		$labelAttributes['for'] = $options['id'];
+		if (in_array($options['type'], ['radio', 'multicheckbox'], true)) {
+			$labelAttributes['for'] = false;
+		}
 		if ($options['nestedInput']) {
 			$labelAttributes['input'] = $options['input'];
 		}

tests/TestCase/View/Helper/FormHelperTest.php

@@ -3395,7 +3395,7 @@ public function testInputRadio() {
 		]);
 		$expected = [
 			['div' => ['class' => 'input radio']],
-				['label' => ['for' => 'test']],
+				'<label',
 				'Test',
 				'/label',
 				['input' => ['type' => 'hidden', 'name' => 'test', 'value' => '']],
@@ -4227,7 +4227,7 @@ public function testInputMultiCheckbox() {
 		]);
 		$expected = [
 			['div' => ['class' => 'input multicheckbox']],
-			['label' => ['for' => 'category']],
+			'<label',
 			'Category',
 			'/label',
 			'input' => ['type' => 'hidden', 'name' => 'category', 'value' => ''],
@@ -6405,7 +6405,7 @@ public function testInputsNotNested() {
 			['label' => ['for' => 'confirm-n']],
 			'No',
 			'/label',
-			['label' => ['for' => 'confirm']],
+			'<label',
 			'Confirm',
 			'/label',
 			'/div',