Fix Home->Overview grid task not in top-right

- Use expectedCurrentTaskView's position to calculate if we should add extra gap between clear all button, instead of using the right most task's position; this fixed the case where current task is not the right most task e.g. grid task and desktop task
- The accumulated row width to expectedCurrentTaskView is tracked in the udpateGridProperties loop, and used to calculate the position of the expected position of expectedCurrentTaskView from ClearAllButton
- With this new calculation we no longer needs to adjust longRowWidth when there are onlg large tile tasks

Fix: 391306182
Test: With and without grid-only Overview, test both home and app to Overview with 0-5 tasks with a desktop task; repeat for RTL
Flag: EXEMPT BUG_FIX
Change-Id: I324208c7e063c8b043815291cc0fef7beec884b6