[Feature]: Ensure pages for uploads are indexed as seeds

[ikreymer]

What change would you like to see?

When pages from uploads are indexed, they should be marked as seeds if:

• seed flag is set in the page json
• if the pages comes from pages.jsonl, but not extraPages.jsonl

This way, existing uploads from ArchiveWeb.page will have their pages marked as seeds, and will appear in the list. Crawls uploaded from a different Browsertrix / Browsertrix Crawler will also have pages indexed correctly, as they should have the seed flag set already and using pages.jsonl / extraPages.jsonl

Context

Ensure uploads appear correctly in collections with the new collection loading optimizations.