Use per-vendor release note details

[DRSDavidSoft]

Summary

• Change generated vendor update PR release notes from one large collapsible block to one collapsible <details> block per updated vendor.
• Add a GitHub release shield per vendor in the update table.
• Put the compare link at the end of each vendor release-note blockquote as "View full changes".
• Apply 👆 Dependencies and 🗃️ Vendor labels to generated vendor update PRs.

Label check

• 👆 Dependencies already exists and is already used by Dependabot.
• 🔄️ GitHub Actions already exists and is already used by Dependabot.
• Created 🗃️ Vendor (#0366d6) for vendored dependency update PRs.

Validation

• git diff --check
• Executed the updated PR-body generation logic locally against the ⬆️ Update 4 vendored dependencies #3093 version set and verified it emits four vendor-specific <details> blocks, four GitHub release shields, and four final blockquoted compare links.