TCLOUD-4873: Remove obsolete method of creating preview

[tiny-james]

Ticket: TCLOUD-4873

Site: Staging branch

Changes:

• Remove the old github workflow that uploaded the preview to a bucket per-branch. It is superseded by the new workflow that uses folders and versioning in a single bucket.

Pre-checks:

• [x] Branch prefixed with feature/<version>/, hotfix/<version>/, staging/<version>/, or release/<version>/.
• [x] modules/ROOT/nav.adoc has been updated (if applicable).
• [x] Included a release note entry for any New product features.
• [x] If this is a minor release, updated productminorversion in antora.yml and added new supported versions entry in modules/ROOT/partials/misc/supported-versions.adoc.

Review:

• [ ] Documentation Team Lead has reviewed