Remove unused milkdrop-preset-converter-aws dependency

Not imported anywhere in the source. It was pulling in babel-runtime@6
and core-js@2 as transitive dependencies for consumers.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/webamp/package.json

@@ -136,7 +136,6 @@
     "invariant": "^2.2.3",
     "jszip": "^3.10.1",
     "lodash": "^4.17.21",
-    "milkdrop-preset-converter-aws": "^0.1.6",
     "music-metadata": "^11.6.0",
     "music-metadata-browser": "^0.6.1",
     "react": "^19.1.0",

pnpm-lock.yaml

@@ -347,9 +347,6 @@ importers:
       lodash:
         specifier: ^4.17.21
         version: 4.17.21
-      milkdrop-preset-converter-aws:
-        specifier: ^0.1.6
-        version: 0.1.6
       music-metadata:
         specifier: ^11.6.0
         version: 11.6.0