Reduces vertical padding of predicted apps in All Apps.

Rather than using the full allAppsCellHeight, manually construct
the icon + padding + text and add custom padding (8dp).

Screenshots: https://drive.google.com/drive/folders/1hgEE72PaTj60SxgfPUzQ8hGwnCOWx-Lp?resourcekey=0-TgrHKITyzIXmNAAMYpA_MA&usp=sharing

Fix: 242915342
Test: Manual inspection
Change-Id: Ic566e0f7ea7cf486054bb8fe2429ee5c53e8b174

src/com/android/launcher3/allapps/FloatingHeaderView.java

@@ -272,7 +272,8 @@ public class FloatingHeaderView extends LinearLayout implements
         }
         mMaxTranslation += mFloatingRowsHeight;
         if (!mTabsHidden) {
-            mMaxTranslation += mTabsAdditionalPaddingBottom;
+            mMaxTranslation += mTabsAdditionalPaddingBottom
+                    + getResources().getDimensionPixelSize(R.dimen.all_apps_tabs_margin_top);
         }
     }