Simplify NPE checking code

Author: bilal-alsharifi

base/src/main/java/com/smartdevicelink/managers/screen/menu/BaseMenuManager.java

@@ -175,10 +175,9 @@ public void setMenuCells(@NonNull List<MenuCell> cells){
 		if (currentHMILevel == null || currentHMILevel.equals(HMILevel.HMI_NONE) || currentSystemContext.equals(SystemContext.SYSCTXT_MENU)){
 			// We are in NONE or the menu is in use, bail out of here
 			waitingOnHMIUpdate = true;
-			if (clonedCells == null) {
-				waitingUpdateMenuCells = new ArrayList<>();
-			} else {
-				waitingUpdateMenuCells = new ArrayList<>(clonedCells);
+			waitingUpdateMenuCells = new ArrayList<>();
+			if (clonedCells != null) {
+				waitingUpdateMenuCells.addAll(clonedCells);
 			}
 			return;
 		}
@@ -190,10 +189,9 @@ public void setMenuCells(@NonNull List<MenuCell> cells){
 			oldMenuCells = new ArrayList<>(menuCells);
 		}
 		// copy new list
-		if (clonedCells == null) {
-			menuCells = new ArrayList<>();
-		} else {
-			menuCells = new ArrayList<>(clonedCells);
+		menuCells = new ArrayList<>();
+		if (clonedCells != null) {
+			menuCells.addAll(clonedCells);
 		}
 
 		// HashSet order doesnt matter / does not allow duplicates