Summary:
Refine shadows in order to match decoration shadows. See D11069

The refined KStyle shadows(from Small to Very Large)
{F5754393, layout=center, size=full}

Desktop experience with the refined shadows
{F5754394, layout=center, size=full}

Depends on D11198

Reviewers: #breeze, #vdg, hpereiradacosta

Reviewed By: hpereiradacosta

Subscribers: abetts, ngraham, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D11175