Update the swimlane epic title shadow to follow the UI guidelines

Everyone can contribute. Help move this issue forward while earning points, leveling up and collecting rewards.

• Close this issue

The following discussion from !122017 (merged) should be addressed:

• @euko started a discussion: (+3 comments)

  @nickbrandt

  Thanks @emilybauman for pointing this out! I agree the shadow here doesn't look great. What was used is also not aligned with types of shadows we have in our guidelines. I'm aligned with you that a thin line would probably be better here, similar to what we do for sticky headers on Issues/MRs.