Make GridModel.defaultGroupSortFn null-safe and improve type signat…

[ghsolomon]

…ure (+GridGroupSortFn type).

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• Caught up with develop branch as of last change.
• Added CHANGELOG entry, or determined not required.
• Reviewed for breaking changes, added breaking-change label + CHANGELOG if so.
• Updated doc comments / prop-types, or determined not required.
• Reviewed and tested on Mobile, or determined not required.
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[Copilot]

Pull Request Overview

This pull request enhances the null-safety of GridModel.defaultGroupSortFn and improves the type signature for GridGroupSortFn while refactoring the group sort logic in InstancesModel.

• Updated sorting logic in InstancesModel to use more descriptive variables.
• Improved typing of GridGroupSortFn parameters in Types.ts.
• Introduced a null-safe defaultGroupSortFn in GridModel.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
inspector/instances/InstancesModel.ts	Refactored groupSortFn to introduce explicit sort values for comparison.
cmp/grid/Types.ts	Updated type signature of GridGroupSortFn from any to string.
cmp/grid/GridModel.ts	Added a null-safe defaultGroupSortFn and removed duplicate definitions.
CHANGELOG.md	Updated changelog to reflect bug fixes and type signature improvements.

Comments suppressed due to low confidence (1)

inspector/instances/InstancesModel.ts:267

• [nitpick] Consider extracting the hard-coded 'Watchlist' string into a well-named constant to improve maintainability and reduce potential errors.

const sortValA = a === 'Watchlist' ? 0 : 1,