Revisit parallel funnel ordering on close timestamps

[SebastienGllmt]

When running parallel funnels, blocks from 2 different chains may have the same timestamp

Currently, Paima Engine will break ties depending on the order the funnels are specified in your config file

However, there are a few things that make this behavior not obvious:

1. It's not mentioned in our docs
2. It's not explicitly enforced in the code (this just a result of the way JS internals work with Object.key and YAML.parse)
3. This tie-breaker logic doesn't just happen when the timestamps are equal - it happens when different chains are fetched from the same getSyncRoundData

This behavior is not immediately obvious to users or developers, so we should make the behavior as obvious as possible and properly document it.