Pinning aggregation rows then ungrouping causes a hard error

[Mike-Dax]

TanStack Table version

8.20.5

Framework/Library version

React 17.0.2

Describe the bug and the steps to reproduce it

This reproduction is a combination of the pinning and grouping example sandboxes.

1. Group some rows, eg 'last names' by clicking ✋.
2. Pin a grouped aggregation row by clicking ⬆️ or ⬇️.
3. Ungroup the rows by clicking ✊.

In this code:

https://github.com/TanStack/table/blob/6b4d616dd7c8917616eb4fecaf09dda7030fd115/packages/table-core/src/features/RowPinning.ts#L233-L247C30

table.getRow(rowId, true) is called on an aggregation row that no longer exists, and the component errors ungracefully.

Your Minimal, Reproducible Example - (Sandbox Highly Recommended)

https://stackblitz.com/edit/tanstack-table-s94mcy?file=src%2Fmain.tsx

Screenshots or Videos (Optional)

No response

Do you intend to try to help solve this bug with your own PR?

Yes, I am also opening a PR that solves the problem along side this issue

Terms & Code of Conduct

• I agree to follow this project's Code of Conduct
• I understand that if my bug cannot be reliable reproduced in a debuggable environment, it will probably not be fixed and this issue may even be closed.