Provide an option to fetch Batch Instance ID from journey properties attributes in expression editor

[#1]

Description -

Currently in the journey expression editor, batch instance ID is not available in properties. It would be ideal to have batch instance ID and use it for reporting purposes.

Why is this feature important to you -

Not every customer would rely on Data Distiller query to fetch batch instance id from journey step events dataset. Batch Instance ID is helpful to identify different cohorts in a recurring batch audience triggered journeys.

How would you like the feature to work -

Provide ${journeyBatchInstanceId} property in the journey expression editor.

Current Behaviour -

${journeyBatchInstanceId} is not available.