feat(abstract-utxo): remove unspents dependency

Remove @bitgo/unspents dependency as it's no longer needed with the
wasm-utxo implementation.

Issue: BTC-2891

Co-authored-by: llm-git <llm-git@ttll.de>

Author: OttoAllmendinger

modules/abstract-utxo/package.json

@@ -64,7 +64,6 @@
     "@bitgo/sdk-api": "^1.73.4",
     "@bitgo/sdk-core": "^36.30.0",
     "@bitgo/secp256k1": "^1.10.0",
-    "@bitgo/unspents": "^0.51.0",
     "@bitgo/utxo-core": "^1.32.0",
     "@bitgo/utxo-lib": "^11.20.0",
     "@bitgo/utxo-ord": "^1.25.0",