[EPIC] Further clean up aggregation implementation

[2010YOUY01]

Is your feature request related to a problem or challenge?

Follows up #22710

Describe the solution you'd like

We have completed the migration functionally in #22710, there are some remaining cleanup items to be done after that:

• Remove the old implementation in grouped_hash_stream.rs after 56.0 release (keep 1 more release in case of major bugs, and we can still use config to switch back)
• Simplify AggregateHashTable<PartialSkip> #23113
• Use builder pattern for constructors: refactor(hash-aggr): Support spilling for ordered aggregation #23657 (comment)
• The existing control flow repeatedly construct Controlflow::Break, caused large LoC: refactor(hash-aggr): Support spilling for ordered aggregation #23657 (comment)
• refactor(hash-aggr): Support spilling for ordered aggregation #23657 (comment)
• Extract common aggregation spill logic #24317
• Cleanup aggregation planning #24318

For coordination: I plan to do them shortly, but if we're about to ship major features like #24704, feel free to ping me and I'll pause to avoid conflicts.

Describe alternatives you've considered

No response

Additional context

No response

[alamb]

Nice -- thank you