feature request: if there are no blobs, empty vector is returned. document anything else that changes from a user perspective

[jcstein]

          makes sense, thanks! and in this feature, if there are no blobs, empty vector is returned? is there anything else that changes from a user perspective?

Originally posted by @jcstein in https://github.com/celestiaorg/celestia-node/issues/3223#issuecomment-1983806958

cc @vgonkivs for help on UX changes