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) {
```
}
                }
            }
        }
        if (chain) {
            Instance->chainStateFlushed(chain->getTipLocator());
        }
    } else if (_creation_flags & WALLET_FLAG_DISABLE_PRIVATE_KEYS) {
        // Make it impossible to disable private keys after creation
        error = strprintf(_("Error loading %s Private keys can only be disabled during creation"), File);
        return nullptr;
    } else if (Instance->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
        for (auto spk_man  Instance->GetActiveScriptPubKeyMans()) {
            if (spk_man->HavePrivateKeys()) {
                warnings.push_back(strprintf(_("Warning Private keys detected in  {%s} with disabled private keys"), File));
                break;
            }
        }
    }
    if (!args.GetArg("-addresstype", "").empty()) {
        stdoptional<OutputType> parsed = ParseOutputType(args.GetArg("-addresstype", ""));
        if (!parsed) {
            error = strprintf(_("Unknown address type '%s'"), args.GetArg("-addresstype", ""));
            return nullptr;
        }
        Instance->m_default_address_type = parsed.value();
    }
    if (!args.GetArg("-changetype", "").empty()) {
        stdoptional<OutputType> parsed = ParseOutputType(args.GetArg("-changetype", ""));
        if (!parsed) {