Attempting to load a wallet with an unknown descriptor causes a fatal error:

```
2022-09-06T01:51:06Z init message: Loading wallet…
2022-09-06T01:51:06Z [descriptor] Invalid descriptor: Can only have tr at top level: iostream error
2022-09-06T01:51:06Z [descriptor] Invalid descriptor: Can only have tr at top level: iostream error
2022-09-06T01:51:06Z [descriptor] Setting spkMan to active: id = 50e6032b4d1d62c020ebb6a4d0c8fafc6f01ea80f4d2a41c1a256086611636e9, type = legacy, internal = false
2022-09-06T01:51:06Z [descriptor] Setting spkMan to active: id = 7f709abbde61e8c253798375692bf41202e625ed74a65f9474d464be34fb2870, type = p2sh-segwit, internal = false
2022-09-06T01:51:06Z [descriptor] Setting spkMan to active: id = 2dc6c34099e0ca1235fc990a51042967ecbc8c8ac57062f964739cba2f451be8, type = bech32, internal = false
2022-09-06T01:51:06Z [descriptor] Setting spkMan to active: id = 8d3c63ea1ac9936e789713dc8bae857d328ff029ab9392e67c716752e9b11b0c, type = bech32m, internal = false
2022-09-06T01:51:06Z [descriptor] Releasing wallet
2022-09-06T01:51:06Z 

************************
EXCEPTION: St12out_of_range       
map::at       
bitcoin in Runaway exception       



************************
EXCEPTION: St12out_of_range       
map::at       
bitcoin in Runaway exception       

bitcoin-qt: ./checkqueue.h:204: CCheckQueue<CScriptCheck>::~CCheckQueue() [T = CScriptCheck]: Assertion `m_worker_threads.empty()' failed.
Aborted
```

> A fatal error occurred. Bitcoin Core can no longer continue safely and will quit.

To reproduce, a quick hack:

```c++
--- a/src/script/descriptor.cpp
+++ b/src/script/descriptor.cpp
@@ -1408,7 +1408,7 @@ std::unique_ptr<DescriptorImpl> ParseScript(uint32_t& key_exp_index, Span<const
         error = "Can only have addr() at top level";
         return nullptr;
     }
-    if (ctx == ParseScriptContext::TOP && Func("tr", expr)) {
+    if (ctx == ParseScriptContext::TOP && Func("trx", expr)) {
         auto arg = Expr(expr);
         auto internal_key = ParsePubkey(key_exp_index, arg, ParseScriptContext::P2TR, out, error);
         if (!internal_key) {
```
WalletBatch batch(GetDatabase());
    if (!batch.WriteActiveScriptPubKeyMan(static_cast<uint8_t>(type), id, internal)) {
        throw stdruntime_error(stdstring(__func__) + " writing active ScriptPubKeyMan id failed");
    }
    LoadActiveScriptPubKeyMan(id, type, internal);
}
void CWalletLoadActiveScriptPubKeyMan(uint256 id, OutputType type, bool internal)
{
    // Activating ScriptPubKeyManager for a given output and change type is incompatible with legacy s.
    // Legacy s have only one ScriptPubKeyManager and it's active for all output and change types.
    Assert(IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS));
    WalletLogPrintf("Setting spkMan to active id = %s, type = %s, internal = %s\n", id.ToString(), FormatOutputType(type), internal ? "true"  "false");
    auto& spk_mans = internal ? m_internal_spk_managers  m_external_spk_managers;
    auto& spk_mans_other = internal ? m_external_spk_managers  m_internal_spk_managers;
    auto spk_man = m_spk_managers.at(id).get();
    spk_mans[type] = spk_man;
    const auto it = spk_mans_other.find(type);
    if (it != spk_mans_other.end() && it->second == spk_man) {
        spk_mans_other.erase(type);
    }
    NotifyCanGetAddressesChanged();
}
void CWalletDeactivateScriptPubKeyMan(uint256 id, OutputType type, bool internal)
{
    auto spk_man = GetScriptPubKeyMan(type, internal);
    if (spk_man != nullptr && spk_man->GetID() == id) {
        WalletLogPrintf("Deactivate spkMan id = %s, type = %s, internal = %s\n", id.ToString(), FormatOutputType(type), internal ? "true"  "false");
        WalletBatch batch(GetDatabase());
        if (!batch.EraseActiveScriptPubKeyMan(static_cast<uint8_t>(type), internal)) {
            throw stdruntime_error(stdstring(__func__) + " erasing active ScriptPubKeyMan id failed");