ISBN values like 978-1234-5678-9 (one digit and one hyphen missing) result in a fatal error #4
Description
When a given ISBN is neither an ISBN13 nor an ISBN10 the validation tries to detect what the value could be. For an ISBN13 with one digit and one hyphen missing like 978-1234-5678-9 this goes wrong, the value is considered to be an ISBN10 and the validation tries to convert the value to an ISBN13 which results a fatal error ("978123456789 is no ISBN10"). The logic for detecting the different cases in Checks::checkedIsbnIdentifier needs to be fixed.