perf(site-award): query for game_sets in SeparateAwards()

[wescopeland]

This PR migrates SeparateAwards() to use game_sets instead of GameAlternatives.

After #3065 is merged, to the best of my knowledge, this is the only place actually querying for GameAlternatives.

While working on this function, I couldn't help but notice that SeparateAwards() is wildly inefficient. With the changes in this PR, I was able to drop the number of queries on at least one developer's user profile by ~40.

This PR:

• Consolidates all the queries into a single optimized query using whereIn.
• Uses array flipping for O(1) lookups instead of repeated array searches.
• Pre-calculates award type checks to avoid redundant calls.
• Processes awards in a single execution pass wherever possible.
• Uses early returns to skip unnecessary processing for empty event awards.

[wescopeland]

After #3067 is merged, I will fix this branch.