Security/NonceVerification: add test with PHP 8.1+ nested enum

Just like other nested constructs, the search for a nonce check should limit itself to the current scope and skip over nested closed scopes/not look outside the current scope.

This is already handled correctly for enums due to the sniff using the PHPCSUtils `Collections::closedScopes()` method.

This just adds tests to safeguard this.

WordPress/Tests/Security/NonceVerificationUnitTest.1.inc

@@ -459,3 +459,30 @@ function test_match() {
 		default => $_POST['key'], // OK, due to check above. Realistically, this is wrong, but that goes for all conditional checks.
 	};
 }
+
+function function_containing_nested_enum_with_nonce_check() {
+	enum MyEnum {
+		public function nested_method() {
+			wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['my_nonce'] ) ), 'the_nonce' );
+		}
+	}
+
+	echo $_POST['foo']; // Bad.
+}
+
+function function_containing_nested_enum_with_nonce_check_outside() {
+	wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['my_nonce'] ) ), 'the_nonce' );
+
+	enum MyEnum {
+		public function nested_method() {
+			echo $_POST['foo']; // Bad.
+		}
+	}
+}
+
+enum MyEnum {
+	public function nested_method() {
+		wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['my_nonce'] ) ), 'the_nonce' );
+		echo $_POST['foo']; // OK.
+	}
+}

WordPress/Tests/Security/NonceVerificationUnitTest.php

@@ -74,6 +74,8 @@ public function getErrorList( $testFile = '' ) {
 					438 => 1,
 					448 => 1,
 					453 => 1,
+					470 => 1,
+					478 => 1,
 				);
 
 			case 'NonceVerificationUnitTest.2.inc':