fix(planner): Fix aggregation in cluster mode

[leiysky]

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Summary

We derived the wrong data distribution of aggregation if there is more than one group key since we will actually use an internal column _group_by_key as the distribute key which cannot be recognized during planning for now.

This can be improved in the future.

Close #8290
Close #8292

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1 Ignored Deployment

Name	Status	Preview	Updated
databend	⬜️ Ignored (Inspect)		Oct 19, 2022 at 8:19AM (UTC)

[mergify]

This pull request's title is not fulfill the requirements. @leiysky please update it 🙏.

Valid format:

fix(query): fix group by string bug
  ^         ^---------------------^
  |         |
  |         +-> Summary in present tense.
  |
  +-------> Type: rfc, feat, fix, refactor, ci, docs, chore

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