Switch the JS script used for running the docs examples tests from
CommonJS to ESM format. This is necessary for upgrading the `globby`
dependency to [version 12.0.0][1] in a subsequent commit.
[1]: https://github.com/sindresorhus/globby/releases/v12.0.0
PR Close#42921
Previously, some RxJS-related examples (which are not proper Angular apps) were not
tested on CI as part of the `example-e2e` npm script. This meant that the examples
could get out-of-date or contain compile errors without as noticing.
This commit ensures that the `example-e2e` script picks up these examples and checks
that they compile successfully.
Partly addresses #28017.
PR Close#34063
