Remove org.jboss.as.cli import from AbstractMgmtTestBase

AbstractMgmtTestBase imports org.jboss.as.cli.operation.OperationFormatException because executeAndRollbackOperation declares it throws it. But the method doesn't actually throw that exception.

As a result there are a bunch of in-vm arquillian tests in WildFly that base on AbstractMgmtTestBase that are adding to their deployments the org.jboss.as.cli module as a MANIFEST>MF dependency. Remove this import and they won't need to do that. Don't do that and some of those test can then be executed against a Galleon-slimmed installation, i.e one without the CLI installed.