refactor: remove unreachable code in MsgV3

lib/msg-v3/index.js

@@ -160,9 +160,6 @@ function create(opts) {
       const prev = [...union(lipmaaSet, tangle.tips)].sort()
       tangles[rootID] = { depth, prev }
     }
-  } else {
-    // prettier-ignore
-    throw new Error(`cannot create msg without tangles, that's the case for createMoot()`)
   }
 
   /** @type {Msg} */