Display "Removing Rekey" warning when rekeying to same account

[nullun]

I've just spoken with an individual who ended up rekeying their account, then rekeying it again back to their original account under the assumption that it was still somehow rekeyed. I tested on my own device and sure enough it treats it like any other rekey even though the protocol is removing the rekey.

I'd recommend displaying a warning like "This action will remove your rekey" if already rekeyed, or disallow the action all together if the account isn't already rekeyed.