Limit the recommendations space in two pane picker

- This makes the suggestion section non-overwhelming
- Currently it shows too many suggestions for user to find any value
- Limiting the height also allows pagination to feel smooth when showing
in categories

Bug: 318410881
Flag: ACONFIG com.android.launcher3.enable_categorized_widget_recommendations DEVELOPMENT
Test: Manual
Change-Id: Iab1f9a15bdd46ee1560734e30551bfb7c8a74a82