Migrate ENABLE_GRID_ONLY_OVERVIEW to aconfig

- Keeping FeatureFlags.ENABLE_GRID_ONLY_OVERVIEW for local testing until aconfig is available in FlagFlipper
- Still reference ENABLE_GRID_ONLY_OVERVIEW in tests as aconfig still can't be mocked

Bug: 270397206
Test: manual
Change-Id: I799e05311adc21184a6ad7ce92a3abdab3f25c25
diff --git a/src/com/android/launcher3/DeviceProfile.java b/src/com/android/launcher3/DeviceProfile.java
index e7d1db4..cde3536 100644
--- a/src/com/android/launcher3/DeviceProfile.java
+++ b/src/com/android/launcher3/DeviceProfile.java
@@ -1715,7 +1715,7 @@
 
     /** Gets the space that the overview actions will take, including bottom margin. */
     public int getOverviewActionsClaimedSpace() {
-        int overviewActionsSpace = isTablet && FeatureFlags.ENABLE_GRID_ONLY_OVERVIEW.get()
+        int overviewActionsSpace = isTablet && FeatureFlags.enableGridOnlyOverview()
                 ? 0
                 : (overviewActionsTopMarginPx + overviewActionsHeight);
         return overviewActionsSpace + getOverviewActionsClaimedSpaceBelow();