[Multiline] Clean-up multiline flag on Launcher3

Bug: b/409605328
Flag: EXEMPT removing multiline_search_bar
Test: Unit tests all passing
Change-Id: Id377b7c99af0d0265102888b8021c0809f53a6b9

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

@@ -779,9 +779,7 @@ public class ActivityAllAppsContainerView<T extends Context & ActivityContext>
      * request {@link FloatingHeaderView} to update its maxTranslation for multiline search bar.
      */
     public void forceUpdateHeaderHeight(int offset) {
-        if (Flags.multilineSearchBar()) {
-            mHeader.updateSearchBarOffset(offset);
-        }
+        mHeader.updateSearchBarOffset(offset);
     }
 
     @Override