ZEVA 2 - IDIR Vehicle Suppliers -Add Total Current ZEV Credits to the Credit Transactions Tab Current Balance

**Describe the task**
Update the Credit Transactions tab for an existing Vehicle Supplier by adding a Total Current ZEV Credits summary to the Current Balance section.
Currently, the Current Balance table displays balances by compliance year and credit type. The updated design introduces an additional summary row displayed above the yearly balances.

**Purpose**
Provide users with an immediate view of the supplier’s total current ZEV credits

**Acceptance Criteria**
- [x] The Current Balance section includes a Total Current ZEV Credits summary.
- [x] The summary is displayed above the compliance year rows, as shown in the [approved design.](https://www.figma.com/design/7Qgou3rxcHHk5qbmD9538x/ZEVA-2?node-id=3231-9508&t=xpdupCduTye12Tml-1)
- [x] The layout, typography, spacing, and styling match the approved Figma design.