Remove feature flag `product_analytics_snowplow_support`

What does this MR do and why?

Removal of the product_analytics_snowplow_support feature flag as it's no longer needed

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #403418 (closed)