bug: Cold Staking outputs invisible to /v2/utxo/ API

[JSKitty]

Cold Staking outputs are often impossible to see via the /api/v2/utxo/ endpoint, which is a critical component for My PIVX Wallet to collect and compute Cold Staking information.

A real-world example:
The PIVX Labs address (/api/v2/address/<addr>)
A Cold Staking UTXO from it (/api/v2/tx-specific/<txout>)

As seen, a 400+ PIV delegation is entirely 'missing' from the UTXO API and is not correlated with the PIVX Labs address, this makes it incredibly difficult to figure out one's Cold Staking UTXOs.

To verify this UTXO is unspent, you can run this in a synced PIVX Core, if it returns data, then the output is proven unspent:

Debug Console:
gettxout 34da1189d5f1e8467ce9db46fc4ce06d689c9b870bc858b92a4ded5b89c7bbab 1

OR via CLI:
./pivx-cli gettxout 34da1189d5f1e8467ce9db46fc4ce06d689c9b870bc858b92a4ded5b89c7bbab 1

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💰 A bounty of 250 PIV is attached to this issue by Labs

[JSKitty]

🪙 250 PIV bounty fulfilled and sent