Refactor code to SonarQube standards
commit 3b78f329 Author: David Meng xlmeng@amazon.com Date: Wed Jul 27 2022 17:04:01 GMT-0400 (Eastern Daylight Time)
Rename the field to avoid shadowing the parent class field; add an assertion to the test case; refactor the method isDomainAdminServiceAccount to remove the nested if statement.