Description of problem:
Querying for a Sync status of a Sync Plan or a Product via API endpoints:

GET /katello/api/sync_plans/:id
GET /katello/api/v2/products?organization_id=:id&sync_plan_id=:id
(possibly others)

return sync status of the very last repository within the Sync Plan or Product. That is sometimes confusing, when you:

• sync 5 repos of a product, 4 of them fail
• now, the sync status shows "Incomplete sync"
• as the latest sync relevant to the product was bulk task of syncing 5 repos, that (partially) failed
• syncing one of failed repos succeeds
• now, the sync status shows "Syncing Complete." for the whole product / sync plan
• as the latest sync relevant to the product was a single repo sync that succeeded - ignoring the other repos failed during their latest sync

This logic "take an outcome of latest product-relevant sync, regardless of the sync scope" should be be either documented (in APIdoc also), or improved to query each and every repo of the product.

Version-Release number of selected component (if applicable):
Sat 6.11.

How reproducible:
100%

Steps to Reproduce:
1. Have a custom product with 2 repos, one with valid feed URL, second with invalid URL
2. Create a Sync Plan for the Product
2. Sync Product and check sync status of the Sync Plan / Product
3. Sync just the correct repo

Actual results:
2. Shows "Incomplete sync." (which is correct)
3. Shows "Syncing Complete.", despite nothing really changed from point 2.

Expected results:
3. to show "Incomplete sync" OR document this behaviour as described above

Additional info: