chore(deps): bump @scure/btc-signer from 1.6.0 to 1.8.1 in /sdk

Bumps [@scure/btc-signer](https://github.com/paulmillr/scure-btc-signer) from 1.6.0 to 1.8.1.
- [Release notes](https://github.com/paulmillr/scure-btc-signer/releases)
- [Commits](paulmillr/scure-btc-signer@1.6.0...1.8.1)

---
updated-dependencies:
- dependency-name: "@scure/btc-signer"
  dependency-version: 1.8.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

sdk/package-lock.json

@@ -44,7 +44,7 @@
         "@gobob/sats-wagmi": "^0.3.23",
         "@magiceden-oss/runestone-lib": "^1.0.2",
         "@scure/base": "^1.2.4",
-        "@scure/btc-signer": "^1.6.0",
+        "@scure/btc-signer": "^1.8.1",
         "bitcoin-address-validation": "^3.0.0",
         "bitcoinjs-lib": "^6.1.7",
         "ethers": "^6.14.4",