Revert commit after Spring Security is migrated

[ilopmar]

Once SpringSecurity is migrated:

• Rever this commit: https://github.com/grails/grails3-functional-tests/commit/7efa7effaab70018b1589b6794f93108198aa2c4
• Externalize and configure new Spring Security version in https://github.com/grails/grails3-functional-tests/blob/merge-33x-in-master/plugins/loadafter/build.gradle#L49

[ilopmar]

I will add a new one with the updated information because there are more things needed.