Resolve "Followup: Activity feed timeline extends to far on Starred Projects and Followed users"

What does this MR do and why?

Unifies the timeline (gray line) on all filters of the activity widget on the personal homepage

References

Followup: Activity feed timeline extends to far... (#565007 - closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

• Enable the personal_homepage feature flag.
• Go to http://gdk.test:3000/dashboard/home

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #565007 (closed)