[Attentive] - new Ecommerce Action for Attentive

[joe-ayoub-segment]

WIP

Testing

Include any additional information about the testing you have completed to
ensure your changes behave as expected. For a speedy review, please check
any of the tasks you completed below during your testing.

• Added unit tests for new functionality
• Tested end-to-end using the local server
• [If destination is already live] Tested for backward compatibility of destination. Note: New required fields are a breaking change.
• [Segmenters] Tested in the staging environment
• [Segmenters] [If applicable for this change] Tested for regression with Hadron.

[github-actions]

New required fields detected

Warning

Your PR adds new required fields to an existing destination. Adding new required settings/mappings for a destination already in production requires updating existing customer destination configuration. Ignore this warning if this PR is for a new destination with no active customers in production.

The following required fields were added in this PR:

• Destination: Attentive, Action Field(s):userIdentifiers,eventType,items
• Destination: Attentive, Action Field(s):userIdentifiers
• Destination: Attentive, Action Field(s):userIdentifiers,subscriptionType
• Destination: Recombee, Action Field(s):userIdentifiers,eventType,items
• Destination: Recombee, Action Field(s):userIdentifiers
• Destination: Recombee, Action Field(s):userIdentifiers,subscriptionType

Add these new fields as optional instead and assume default values in perform or performBatch block.

[joe-ayoub-segment]

FYI @duynguyen100