build(docs-infra): examples should not run ngcc for all formats (#28984)

Currently when adding the example boilerplate to all
examples with Ivy enabled, we run Ngcc and transform
all found formats. This potentially slows down the build and
is not necessary as we only need the "fesm5" and "fesm2015" bundles.

PR Close #28984

aio/tools/examples/example-boilerplate.js

@@ -104,7 +104,12 @@ class ExampleBoilerPlate {
     }
 
     if (ivy) {
-      shelljs.exec(`yarn --cwd ${SHARED_PATH} ivy-ngcc`);
+      // We only need the "fesm5" bundles as the CLI webpack build does not need
+      // any other formats for building and serving. Ngcc currently only updates
+      // the module typings if we specified an "es2015" format. This means that
+      // we also need to build with "fesm2015" in order to get updated typings
+      // which are needed for compilation.
+      shelljs.exec(`yarn --cwd ${SHARED_PATH} ivy-ngcc --formats fesm2015 fesm5`);
     }
 
     exampleFolders.forEach(exampleFolder => {