fix sort by weight instead of topic id; rm excess sort logic

[kpeluso]

Purpose of Changes and their Description

Difference in sorting order across UpdateNoncesOfActiveTopics and EmitRewards was resolved. Code in former sorted on the wrong condition resulting in unintended functionality, possibly including giving rewards to the wrong topics when the number of active topics exceeds MaxActiveTopicsPerBlock.

Was able to remove some excess logic as well.

Link(s) to Ticket(s) or Issue(s) resolved by this PR

https://linear.app/alloralabs/issue/ENGN-3518/171-difference-in-sorting-order-across-updatenoncesofactivetopics-and

Are these changes tested and documented?

• If tested, please describe how. If not, why tests are not needed.
  • Unit tests
• If documented, please describe where. If not, describe why docs are not needed.
  • Executes intended functionality as explained in code comments
• Added to Unreleased section of CHANGELOG.md?

Still Left Todo

Fill this out if this is a Draft PR so others can help.

[amimart]

LGTM