Handle deleted accounts and provide instructions if those are implicit accounts

[frol]

There has been a situation where the implicit account has been converted into a named account, while the lockup contract has been issued for the implicit account id.

https://near.github.io/account-lookup/#ed25519:8tdgHbaBhUoKZnzA4fn4RiDj36JGf2nuH51CRfAczkR8 (this displayed nothing, while it should have displayed that the account is deleted and provide some helpful instructions, see below)

The original implicit account was: https://explorer.near.org/accounts/753be6a50dae345c1c574e186ab30cb7d604639dd67b17660f4c134fa0aebdbb

Then it was converted into a named account, and thus the implicit account has been deleted in favor of https://explorer.near.org/accounts/mikec.near

The lockup has been issued for the implicit account, and here it is: https://explorer.near.org/accounts/46afae1dd24b0ca3796293909c89335c6f215a3a.lockup.near (see the transaction details, which specified the owner account id)

If the owner still has the private key (keypair) corresponding to ed25519:8tdgHbaBhUoKZnzA4fn4RiDj36JGf2nuH51CRfAczkR8 public key, they can transfer 1 NEAR to 753be6a50dae345c1c574e186ab30cb7d604639dd67b17660f4c134fa0aebdbb account id, and thus gaining the control over lockup contract through this implicit account again.