Prevent people to create account ID's with same public key

[vaibhavchellani]

I am not sure if this needs to be prevented at all. But at the moment people are able to get different accountIDs for the same public key, altho it's not possible without actually depositing tokens into Hubble.

[vaibhavchellani]

Not fixing this has an interesting side effect. It allows people to hold one private key and create multiple accounts with different tokens and use the same priv key to sign for all of them.

[vaibhavchellani]

Closing for now.