Azure Storage File Share client library samples for JavaScript

Remove unneeded awaits for PagedAsyncIterableIterators (#9065)

* [storage-blob] clean up container iteration readme

The async iterator is returned synchronously, so no need for the `await`.

* Fix other storage readmes

* Fix a bunch of needless awaits

* Fix overzealous deawaiting

Co-authored-by: Ramya Rao <ramya.rao.a@outlook.com>