refactor: improve typing for useRowGrouping

[ImmortalRabbit]

Introduced rowGroupingMapper with type overload to make sure when itemOrRow is type of number it should return RowGroupingMapperResult<number> and when type if Item it should return RowGroupingMapperResult<Item>

[Copilot]

Pull Request Overview

This PR refactors the typing for the useRowGrouping hook by introducing a new rowGroupingMapper function with proper type overloads to ensure type safety when working with row grouping operations.

Key changes:

• Introduced rowGroupingMapper function with type overloads for number and Item parameters
• Removed the deprecated MapResult interface in favor of RowGroupingMapperResult<T>
• Simplified the RowGroupingMapper type definition

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
packages/core/src/data-editor/row-grouping.ts	Removed MapResult interface and updated mapRowIndexToPath return type
packages/core/src/data-editor/row-grouping-api.ts	Added rowGroupingMapper function with type overloads and refactored the mapper implementation

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[Copilot]

There's a typo in the variable name. It should be flattenedRowGroups.length instead of flattenRowGroups.length. The function parameter is flattenedRowGroups but the condition checks flattenRowGroups (missing 'd').

Suggested change

	if (flattenedRowGroups === undefined || flattenRowGroups.length === 0)
	if (flattenedRowGroups === undefined || flattenedRowGroups.length === 0)

[Copilot]

The RowGroupingMapper type loses type safety by returning a union type RowGroupingMapperResult<Item | number>. This contradicts the purpose of the type overloads in rowGroupingMapper. Consider using function overloads for this type as well to maintain type safety.

Suggested change

	export type RowGroupingMapper = (itemOrRow: number | Item) => RowGroupingMapperResult<Item | number>;
	export type RowGroupingMapper = {
	(itemOrRow: number, flattenedRowGroups?: readonly FlattenedRowGroup[] | undefined): RowGroupingMapperResult<number>;
	(itemOrRow: Item, flattenedRowGroups?: readonly FlattenedRowGroup[] | undefined): RowGroupingMapperResult<Item>;
	};

[Copilot]

The implementation signature includes redundant | undefined since the parameter is already marked as optional with ?. Remove | undefined from the parameter type.

Suggested change

	export function rowGroupingMapper(itemOrRow: number | Item, flattenedRowGroups?: readonly FlattenedRowGroup[] | undefined): RowGroupingMapperResult<number> | RowGroupingMapperResult<Item> {
	export function rowGroupingMapper(itemOrRow: number, flattenedRowGroups?: readonly FlattenedRowGroup[]): RowGroupingMapperResult<number>;
	export function rowGroupingMapper(itemOrRow: Item, flattenedRowGroups?: readonly FlattenedRowGroup[]): RowGroupingMapperResult<Item>;
	export function rowGroupingMapper(itemOrRow: number | Item, flattenedRowGroups?: readonly FlattenedRowGroup[]): RowGroupingMapperResult<number> | RowGroupingMapperResult<Item>;
	export function rowGroupingMapper(itemOrRow: number | Item, flattenedRowGroups?: readonly FlattenedRowGroup[]): RowGroupingMapperResult<number> | RowGroupingMapperResult<Item> {