Remove misbehaviour GetHeight

[colin-axner]

Summary

We are removing FrozenHeight as a notion in core IBC, thus the misbehaviour height isn't useful. It isn't clear in all implementations what height represents misbehaviour. Initially, misbehaviour was viewed as existing only for two conflicting headers at the same height. We now know that misbehaviour can occur at two different heights - making it difficult to distinguish which height is the offending header since presumably an attacker could produce an invalid header on either side of a valid header.

Core IBC should never rely on misbehaviour.GetHeight() thus, it should be removed from the misbehaviour interface

---

For Admin Use

• Not duplicate issue
• Appropriate labels applied
• Appropriate contributors tagged/assigned