[reconfigurator-cli] Add testing for blocked MGS driven updates

[karencfv]

To have better testing it'd be good to have an additional step in the cmds-target-release test that simulate failed MGS updates

Context: #9001 (comment)

Follow up to #9001

[karencfv]

#9044 contains a test that covers the functionality that we're trying to test here. I'll mark this issue as closed once that's merged