Add-ons [DigitalPoint] Better Google Analytics 1.1.2.3

A minor update with the following:

• itemPurchaseQuantity metric updated to itemsPurchased (per breaking changes to Google Analytics Reporting API going into effect Dec 1, 2022)
• New item-scoped metrics added to E-commerce section of weekly heat map (itemsAddedToCart, itemsCheckedOut, itemsViewed and itemsViewedInList)
• Don't try to track emails being read if the outgoing email has no HTML part (emails being sent manually as 'Plain text')

• Suppress error if there is a transient Google Analytics API issue on the main admin page (won't show an error when attempting to display real-time map on the admin index page)
• Changed the explanation text on the debug option to be more clear that it creates server error log entries for debugging server-side events

• Fixed issue where chart dimensions would be mislabeled/incorrectly grouped on the chart
• Added "Purchase revenue" as dimension option for charts
• Added "Item purchase quantity" as dimension option for charts