Backport !5662 - Proto: rename constant to testnet_dictator
Context
!5662 (merged) is required in protocol Kathmandu. Cherry-picked commit from it using the following commands.
$ git checkout -b proto-k-backport-5662
$ git cherry-pick c465a9f76863e697704c79ffd5f123adbf078158
Resolved conflict in tezt/tests/main.ml.
Manually testing the MR
Check CI.