Hide blinding factors for explicit outputs in gettransactoin and listunspent

Currently for explicit outputs gettransaction shows this:
```
    "details": [
        {
            "category": "generate",
            "amount": 0.00104720,
            "amountblinder": "0000000000000000000000000000000000000000000000000000000000000000",
            "asset": "0a8e7509f0ab8b750909e378b51af66158464430b88d8efb0627b0b6226f91ea",
            "assetblinder": "0000000000000000000000000000000000000000000000000000000000000000",
            "vout": 0
        }
```

It's probably better to just hide the blinding factors there instead of showing 00000.

Same for listunspent:
```
{
        "txid": "05df25d4c8c94aaf6c5538d6aed22803abb524cbc6ab115811de3d7716c3e458",
        "vout": 0,
        "scriptPubKey": "51",
        "amount": 0.00104720,
        "asset": "0a8e7509f0ab8b750909e378b51af66158464430b88d8efb0627b0b6226f91ea",
        "amountblinder": "0000000000000000000000000000000000000000000000000000000000000000",
        "assetblinder": "0000000000000000000000000000000000000000000000000000000000000000",
        "confirmations": 8003,
        "spendable": true,
        "solvable": true,
        "desc": "raw(51)#8lvh9jxk",
        "safe": true
}
```

Locate the RPC implementations for gettransaction and listunspent, then inspect how explicit outputs populate amountblinder and assetblinder. The change is done when those blinding-factor fields are omitted for explicit outputs rather than returned as all-zero values, with the affected RPC tests updated or run if present.

Written by the indexing model from the issue text.