[Task Manager] Do not crop album art in tooltip

Summary:
- The standard aspect ratio of `albumImage` is always `1:1`. We should not crop the important part of `albumArt` in some cases.
- Hide the window title text of media players to avoid displaying the title/artist repeatedly.

BUG: 401234
FIXED-IN: 5.16.0

Test Plan:
Before vs After:
- Breeze Dark
{F6691504}
- Breeze Light
{F6691505}

Reviewers: hein, broulik, ngraham, #vdg, filipf, rooty

Reviewed By: ngraham, #vdg, filipf, rooty

Subscribers: mvourlakos, rooty, filipf, ndavis, abetts, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D17073