### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current behaviour

crash

### Expected behaviour

no crash

### Steps to reproduce

* Compile 79e8247ddb166f9b980f40249b7372a502402a4d
* Type `migratewallet`

### Relevant log output

```
wallet/scriptpubkeyman.cpp:1915: std::optional<MigrationData> wallet::LegacyScriptPubKeyMan::MigrateToDescriptor(): Assertion `IsMine(desc_spk) != ISMINE_NO' failed.
Aborted (core dumped)
```


### How did you obtain Bitcoin Core

Compiled from source

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

current master

### Operating system and version

Linux

### Machine specifications

_No response_
{
    LOCK(cs_desc_man);
    return m_wallet_descriptor.creation_time;
}
std::unique_ptr<FlatSigningProvider> DescriptorScriptPubKeyMan::GetSigningProvider(const CScript& script, bool include_private) const
{
    LOCK(cs_desc_man);
    
    auto it = m_map_script_pub_keys.find(script);
    if (it == m_map_script_pub_keys.end()) {
        return nullptr;
    }
    int32_t index = it->second;
    return GetSigningProvider(index, include_private);
}
std::unique_ptr<FlatSigningProvider> DescriptorScriptPubKeyMan::GetSigningProvider(const CPubKey& pubkey) const
{
    LOCK(cs_desc_man);
    
    auto it = m_map_pubkeys.find(pubkey);
    if (it == m_map_pubkeys.end()) {
        return nullptr;
    }
    int32_t index = it->second;
    
    return GetSigningProvider(index, true);
}
std::unique_ptr<FlatSigningProvider> DescriptorScriptPubKeyMan::GetSigningProvider(int32_t index, bool include_private) const