message: fix[webpack-plugin]: avoid removing used stylesheets
  In edge cases, depending on the `node_modules` structure and the number of dynamic imports, webpack may decide the duplicates certain js modules between separate vendor bundles. Stylable's webpack plugin removed the js module (runtime stylesheet) from one of them, which broke runtime evaluation.
diff: @@ -313,12 +313,7 @@ export class StylableWebpackPlugin {
  return chunk.containsModule(r.module);
  }
  });
  - if (!shouldKeep) {
  - if ((m as any).chunksIterable.size === 1) {
  - if (m.buildInfo.isImportedByNonStylable) {
  - return;
  - }
  - }
  + if (!shouldKeep && !m.buildInfo.isImportedByNonStylable) {
  chunk.removeModule(m);
  }
  });
  