housekeeping: cypress standalone failures (via #5446)

* webpack.dist-style.config.js -> webpack-dist-style.config.js

* correctly generate stylesheets in dev server

* attempt to recover from missing StandalonePlugin in Cypress runner

webpack-dist-style.config.js

@@ -0,0 +1,34 @@
+const ExtractTextPlugin = require("extract-text-webpack-plugin")
+
+module.exports = [{ 
+  test: /\.(css)(\?.*)?$/,
+  use: ExtractTextPlugin.extract({
+    fallback: "style-loader",
+    use: [
+      "css-loader",
+      "postcss-loader"
+    ]
+  })
+},
+{ test: /\.(scss)(\?.*)?$/,
+  use: ExtractTextPlugin.extract({
+    fallback: "style-loader",
+    use: [
+      {
+        loader: "css-loader",
+        options: { minimize: true }
+      },
+      {
+        loader: "postcss-loader",
+        options: { sourceMap: true }
+      },
+      { loader: "sass-loader",
+        options: {
+          outputStyle: "expanded",
+          sourceMap: true,
+          sourceMapContents: "true"
+        }
+      }
+    ]
+  })
+}]