feat(wasm-utxo): update package.json files array

Update the files array to only include JS files from the dist directories,
excluding test directory.

Issue: BTC-2786

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

Author: OttoAllmendinger

packages/wasm-utxo/package.json

@@ -9,8 +9,8 @@
   },
   "license": "MIT",
   "files": [
-    "dist/esm/**/*",
-    "dist/cjs/**/*"
+    "dist/esm/js/**/*",
+    "dist/cjs/js/**/*"
   ],
   "exports": {
     ".": {