Fix launch animation from grid

- Fixed calculateGridTaskSize to algin to taskRect instead of gridRect
- Extracted end of grid's scroll diff calculation to getOffsetFromScrollPosition to accurately calculate end of grid task's offset between its scroll and visual position (End of grid task's scroll is all the same at the position where ClearAllButton is just invisible)
- Extracted isGridTask in TaskView so TaskViewSimualtor can use the correct task size depedning if it's grid task or not

Bug: 200813202
Test: manual
Change-Id: I11a980345aee2680abf1c2563baadd9718a40192