Remove unused in product email assets
What does this MR do and why?
Resolves #427341 (comment 1678700858).
Only two places are still using the assets from app/assets/images/mailers/in_product_marketing
, and only two assets are being used, this MR removes the rest.
MR acceptance checklist
Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.
Edited by Roy Liu