Summary:
Diff fixes couple edge cases:
- When changing chart's groupby columns, the data-engine changes the view fields, which is not okay with charts, hence makes sure view fields stay the same as much as possible using `this.setSectionViewFieldsFromArray()`
- Also there's a logic in `this.setSectionViewFieldsFromArray()` that handle what to do when some columns goes missing during updates. Diff fixes this logic two. This is really corner case.
Test Plan: Both cases are not added to ChartAggregate.ts
Reviewers: georgegevoian
Reviewed By: georgegevoian
Differential Revision: https://phab.getgrist.com/D3405