Localization: Locale rows are drawn over the "Name / Code" column header while scrolling in the "Add Locale" popup

Steps to reproduce:

1. Create a new project with 6000.6.0f1
2. Install the Localization package (com.unity.localization)
3. Open Edit > Project Settings > Localization and create the Localization Settings asset
4. Click Add Locale
5. Scroll the locale list
6. Observe the "Name" and "Code" column header row while the list is scrolling

Actual results: Rows scrolling past either end of the list are drawn over the adjacent UI instead of being clipped:

• At the top, a row bleeds through the column header - "Danish" and its code "da" overlap the "Name" and "Code" labels
• At the bottom, a row bleeds through the button row - "Urdu" and its code overlap the "Select All" label, and "Turkish" is struck through by the row edge

Both overlaps leave the affected text unreadable

Expected results: Rows are clipped at the top of the list viewport and pass beneath the column header, which stays opaque and legible

Reproducible with versions: 1.5.12 (6000.6.0f1)

Tested on (OS): MacBook Pro - Tahoe 26.6.2