RepeatingGroup rowsBefore is missing from Summary2 #4188

Description

RepeatingGroup supports both rowsBefore and rowsAfter in the table view,
but Summary2 only renders rowsAfter.

Expected

Summary2 should render both rowsBefore and rowsAfter

Actual

• Table view renders both rowsBefore and rowsAfter
• Summary2 renders only rowsAfter

Code references

• src/layout/RepeatingGroup/index.tsx
  shows both rowsBefore and rowsAfter are part of the component's child handling.
• src/layout/RepeatingGroup/Table/RepeatingGroupTable.tsx
  renders both through ExtraRows.
• src/layout/RepeatingGroup/Summary2/RepeatingGroupTableSummary/RepeatingGroupTableSummary.tsx
  reads and renders rowsAfter, but not rowsBefore.

Reproduction

1. Configure a RepeatingGroup with rowsBefore
2. Verify it appears in the regular table
3. View it in Summary2
4. rowsBefore is missing