Improve vendor update PR details

[DRSDavidSoft]

Summary

• Link each generated vendor PR "New Version" value to the exact GitHub release tag.
• Add a Dependabot-style collapsible release-notes section sourced from vendor release notes, with compare links and blockquoted content.
• Generate the PR emoji legend from the actual table emojis only, and conditionally request cmderdev/trusted-contributors review only when the vendor delta since the previous update-vendor branch includes a major or minor change.

Notes

GitHub does not provide a create/update PR flag to suppress notifications generally. The workflow instead avoids explicit review-request notifications for patch-only updates and requests trusted-contributors only for major/minor changes since the last PR branch update.

Validation

• git diff --check
• Executed the updated PR-body generation logic locally against the version set from ⬆️ Update 4 vendored dependencies #3093 and verified release links, release-note details, exact table emoji legend, and conditional REVIEW_TEAM=trusted-contributors output.