`getaddressinfo` is not printing `confidential_key` with v1 address encoded with blech32m

```
$ elements-cli getnetworkinfo | jq .subversion
"/Elements Core:0.21.0/"
$ elements-cli getaddressinfo lq1pqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq7tgzuvqwaqsv
{
"address": "lq1pqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqszqgpqyqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq7tgzuvqwaqsv",
"scriptPubKey": "51200000000000000000000000000000000000000000000000000000000000000000",
"ismine": false,
"solvable": false,
"iswatchonly": false,
"iswitness": true,
"witness_version": 1,
"witness_program": "0000000000000000000000000000000000000000000000000000000000000000",
"ischange": false,
"labels": [
]
}
```

The address has been generated using rust-elements, see https://github.com/ElementsProject/rust-elements/pull/89#issuecomment-995710483