As IS-IS is a new feature and the CLI configuration changed from 1.3 -> 1.4 (required by T3417) it makes sense to synchronize the CLI configuration for both versions.
This means backporting the CLI from 1.4 -> 1.3 to not confuse the userbase already with a brand new feature.
As 1.3.0-epa1 is on the way and should not contain any CLI changes afterwards, this is the perfect time.