### 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_
while (true) {
        
        DataStream key{};
        DataStream value{};
        DatabaseCursor::Status status = cursor->Next(key, value);
        if (status == DatabaseCursor::Status::DONE) {
            break;
        } else if (status == DatabaseCursor::Status::FAIL) {
            cursor.reset(nullptr);
            m_batch->TxnAbort(); 
            return false;
        }
        
        Span key_data{key};
        std::string type;
        key >> type;
        if (types.count(type) > 0) {
            if (!m_batch->Erase(key_data)) {
                cursor.reset(nullptr);
                m_batch->TxnAbort();
                return false; 
            }
        }
    }
    
    cursor.reset(nullptr);
    return m_batch->TxnCommit();
}
bool WalletBatch::TxnBegin()