signrawtransactionwithkey overrides signatures for segwit multisignature p2wsh address

**Expected behavior**
I have a segwit blinded p2wsh address with:
```
unblinded_address=ex1qf000vr35slcvgrus2qpkqn8ccn7z3hn72uygy4qspghrnc80cflqa2ynaw
redeem_script=52210209e67ac042dfd0b6de4f5829633abe1fd454cc4d28e1cd02d579f5aa9bf0b49521035e39052a6f3245d5f1eea824ddb393b07b181bc728c956c4728dc6ed088628402103c7f33f55a5ca147a58b5a0d3cd1e2cda845fc76015548e9d0d847ce1fc1fb1ec53ae
descriptor=wsh(multi(2,0209e67ac042dfd0b6de4f5829633abe1fd454cc4d28e1cd02d579f5aa9bf0b495,035e39052a6f3245d5f1eea824ddb393b07b181bc728c956c4728dc6ed08862840,03c7f33f55a5ca147a58b5a0d3cd1e2cda845fc76015548e9d0d847ce1fc1fb1ec))#ru8mha3q
blinded_address=lq1qqd45tcekmy6asgfyvklkjms4eet0u47mzw7ugc5avmdd2rmj73y6hze39m2f53wp2mlg0dmruup0ca2fgr3uu43rffdj8yuda
```
And I want to spend the following unspent output from the address:
```
[
{
"txid": "c6b2114d43f9bc2a9397a9126bd1f5a68ebf67ed1962d78b1346e510ed0f8850",
"vout": 0,
"address": "ex1qf000vr35slcvgrus2qpkqn8ccn7z3hn72uygy4qspghrnc80cflqa2ynaw",
"label": "",
"witnessScript": "52210209e67ac042dfd0b6de4f5829633abe1fd454cc4d28e1cd02d579f5aa9bf0b49521035e39052a6f3245d5f1eea824ddb393b07b181bc728c956c4728dc6ed088628402103c7f33f55a5ca147a58b5a0d3cd1e2cda845fc76015548e9d0d847ce1fc1fb1ec53ae",
"scriptPubKey": "00204bdef60e3487f0c40f905003604cf8c4fc28de7e57088254100a2e39e0efc27e",
"amount": 0.00012000,
"assetcommitment": "0a30643bc922512bb45846680eaf492cca0d7775d2e33427d38d76b3942a18dd1d",
"asset": "6f0279e9ed041c3d710a9f57d0c02928416460c4b722ae3457a11eec381c526d",
"amountcommitment": "0881efd8d12c1ee89137b3473a751f8a6f3bf9f882268510eaa573b8b492517b04",
"amountblinder": "2082c51b4e3525b15901cc9aa748e91a0cd6d660e71a455dd1f9e03fa686e426",
"assetblinder": "d895c624e5a1252cf8e8f0c66bb6b00d67b271686936f5344ec6421f0cf3706c",
"confirmations": 442,
"spendable": false,
"solvable": true,
"desc": "wsh(multi(2,[7f4a97af/0'/0'/0']0209e67ac042dfd0b6de4f5829633abe1fd454cc4d28e1cd02d579f5aa9bf0b495,[1b6f657b]035e39052a6f3245d5f1eea824ddb393b07b181bc728c956c4728dc6ed08862840,[b3920fe5]03c7f33f55a5ca147a58b5a0d3cd1e2cda845fc76015548e9d0d847ce1fc1fb1ec))#ppm8xad2",
"safe": true
}
]
```
I made the following transaction with `createrawtransaction` and `fundrawtransaction`:
```
02000000000150880fed10e546138bd76219ed67bf8ea6f5d16b12a997932abcf9434d11b2c60000000000fdffffff02016d521c38ec1ea15734ae22b7c46064412829c0d0579f0a713d1c04ede979026f010000000000002e3b0273171f280c6110c28c83e56bfa773bb39801183b9ef5c2a3f1175e44d34dcc9017a914402e39ed060ed5046ae700684977490092ccd79887016d521c38ec1ea15734ae22b7c46064412829c0d0579f0a713d1c04ede979026f0100000000000000a5000000000000
```
And signing script:
```
blindedtx=$(elements-cli blindrawtransaction $txhex)
privkey=$(elements-cli dumpprivkey $priv_address)
elements-cli signrawtransactionwithkey $notsigned "[\"$privkey\"]" "[ { \"txid\": \"$txid\", \"vout\": $vout, \"scriptPubKey\": \"$script_pubkey\", \"witnessScript\": \"$witness_script\", \"amount\": $amount, \"amountcommitment\": \"$amountcommitment\" } ]"
```
The result seems right, but when I try to sign the transaction with the second private key, the signature from the previous key is overwritten with the new one.

**Actual behavior**

If you consider P2SH "legacy" multisig address, the same process will result in expected multiple signatures in the output.

**System information**

Elements Core RPC client version v0.21.0.0-g134ba2c972a5403fe73bbc9c1877178b3f4d74f9