[ImgBot] Optimize images

*Total -- 418.18kb -> 327.73kb (21.63%)

/src/recommendations/images/event-metric.png -- 21.19kb -> 14.73kb (30.5%)
/src/recommendations/images/snowplow-filter.png -- 109.25kb -> 85.17kb (22.04%)
/src/marketplace/sellers/images/developer-portal-landing-page.png -- 287.74kb -> 227.82kb (20.82%)

Signed-off-by: ImgBotApp <ImgBotHelp@gmail.com>

Author: ImgBotApp