build: (sample) Remove js-miniapp-sdk from package.json dependencies

This was causing errors when trying to run 'yarn install' after updating the sdk's version in it's package.json. The SDK does not need to be declared in depenedencies because Yarn workspaces make it already available.

js-miniapp-sample/package.json

@@ -7,7 +7,6 @@
     "@material-ui/icons": "^4.9.1",
     "axios": "^0.19.2",
     "bowser": "^2.9.0",
-    "js-miniapp-sdk": "0.1.0",
     "react": "^16.13.1",
     "react-dom": "^16.13.1",
     "react-redux": "^7.2.0",