🐛 Showing delegation from de-registered stake keys

### Area

Delegation Pillar

### Domain

gov.tools

### Which wallet were you using?

_No response_

### Context

- When a user de-registers their stake key (rare behaviour but possible) all their delegations to DReps are deleted by the ledger
- If a user delegates to a DRep and then de-registers their stake key, GovTool still shows the user that they are delegated to a DRep, this is incorrect

See example on Preview, for my stake key hash of `994fcbbeddccf13a0771645a9c35b3fd68314be2313817e4dc318194cdb08f92`

I can see that via my test dApp my wallet shows that I do not have any registered stake keys


but when I go to GovTool it shows an active delegation


### Steps to reproduce

1. Delegate to a DRep via Govtool
2. De-Register the wallets stake key - I used https://ryun1.github.io/cip95-cardano-wallet-connector/ to do this
3. Go back to GovTool

### Actual behavior

GovTool shows an active delegation to a DRep

### Expected behavior

GovTool does not show an active delegation to a DRep