Fix missing tags in dataset cards
_The documentation is not available anymore as the PR was closed or merged._
Fix missing tags in dataset cards:
- amazon_us_reviews
- art
- discofuse
- indic_glue
- ubuntu_dialogs_corpus

This PR partially fixes the missing tags in dataset cards. Subsequent PRs will follow to complete this task.

Related to:
- #4833
- #4891
- #4896
- #4908
- #4921
- #4931