#37978: Remove duplicate dependency

I believe it's appropriate to include handlebars in dependencies rather than devDependencies,
because it's imported by multiple js files inside the core directory. However, handlebars-loader
is only referenced inside webpack.common.js, so I think it's ok to keep that one inside devDependencies.

Signed-off-by: JL102 <jordanlees@mailbox.org>

package.json

@@ -150,7 +150,6 @@
     "eslint-plugin-es": "^4.1.0",
     "exports-loader": "^4.0.0",
     "file-loader": "^6.2.0",
-    "handlebars": "^4.7.7",
     "handlebars-loader": "^1.7.3",
     "jasmine-core": "~2.5.2",
     "jasmine-sinon": "^0.4.0",