### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current behaviour

I randomly encountered this by loading a wallet created from master with an older version. I could trace it down to bd13dc2f46ea10302a928fcf0f53b7aed77ad260 (#26076), but I don't know descriptor wallets enough to understand what's going on (cc @Sjors @achow101).

### Expected behaviour

`bitcoind` starts, or at least tells me to use a later version if #26076 was a breaking change instead of corrupting `wallet.dat`.

### Steps to reproduce

(master, clean chain): 
`createwallet -regtest ""`
(v25.0rc2):
first `bitcoind -regtest` succeeds
then stop and restart the node: The second `bitcoind -regtest` leads to an InitError:
`Error: Error: Unable to expand wallet descriptor from cache`
now, the wallet cannot be loaded by either version.

### Relevant log output

_No response_

### How did you obtain Bitcoin Core

Compiled from source

### What version of Bitcoin Core are you using?

v25.0rc2 / master

### Operating system and version

Ubuntu

### Machine specifications

_No response_
{
    return EraseIC(std::make_pair(DBKeys::PURPOSE, strAddress));
}
bool WalletBatch::WriteTx(const CWalletTx& wtx)
{
    return WriteIC(std::make_pair(DBKeys::TX, wtx.GetHash()), wtx);
}
bool WalletBatch::EraseTx(uint256 hash)
{
    return EraseIC(std::make_pair(DBKeys::TX, hash));
}
bool WalletBatch::WriteKeyMetadata(const CKeyMetadata& meta, const CPubKey& pubkey, const bool overwrite)
{
    return WriteIC(std::make_pair(DBKeys::KEYMETA, pubkey), meta, overwrite);
}
bool WalletBatch::WriteKey(const CPubKey& vchPubKey, const CPrivKey& vchPrivKey, const CKeyMetadata& keyMeta)
{
    if (!WriteKeyMetadata(keyMeta, vchPubKey, false)) {
        return false;
    }
    
    std::vector<unsigned char> vchKey;
    vchKey.reserve(vchPubKey.size() + vchPrivKey.size());
    vchKey.insert(vchKey.end(), vchPubKey.begin(), vchPubKey.end());
    vchKey.insert(vchKey.end(), vchPrivKey.begin(), vchPrivKey.end());
    return WriteIC(std::make_pair(DBKeys::KEY, vchPubKey), std::make_pair(vchPrivKey, Hash(vchKey)), false);
}
bool WalletBatch::WriteCryptedKey(const CPubKey& vchPubKey,