Web SDK Release v1.6.9

[KambleSonam]

• Added setLibrary method to set the flutter version
• Fixed the bug in addMultiValueForKey logic
• Added the method markReadInboxMessagesForIds
• Exposed the method toggleInbox to handle the inbox toggle in flutter
• Triggers an event to manage inline script errors related to Content Security Policy.
• Fixes a bug related to Web Inbox scroll.