feature/M095M01A-29 #23: [MAGENTO 2] Make sure we are not sending purges for empty surrogate keys
feature/M095M01A-29 #23: [MAGENTO 2] Make sure we are not sending purges for empty surrogate keys

- Use array_filter to remove any `falsy` elements for surrogate keys array before purge
- Return early if surrogate keys array is empty

fastly/fastly-magento2,fastly/fastly-magento2,fastly/fastly-magento2,fastly/fastly-magento2