* Add purchase task and modal to task list
* Track when cart modal is opened from task list
* Track when extensions are purchased or skipped
* Track checkout proceed on modal close
* Add an array of installed plugins to wcSettings
* Don't include already installed plugins in cart items
* Move cart modal component
* Add purchase task and modal to task list
* Rename ambiguous task getter method
* Remove modal purchase later prop
* Show completed product purchase task item after purchase
* Don't show cart modal if all items previously purchased