Mark applications that play audio, for all task icon sizes

Summary:
Fix cases where indicator not showing. Eg. icon-only task manager.
Place the indicator in the top right corner of the icon. And move it to the side or top if there is enough space.
Audio icon will no more move the task icon off-center.
When placed in the corner, use a smaller click area for muting audio, to avoid accidental mute.
Click area drops to 0.45 and Icon size to 0.63 from what would normally had.

Issues:
Has overlapping issues with other overlays: badge, and group expander.
Poor visibility.
Breeze icon is off center and overlaps(with the blue line at the right). For now,
moved audio icon a touch left, some other theme icons may look off-center.

BUG: 381656
FIXED-IN: 5.18.0

Reviewers: VDG, Plasma, ndavis, ngraham, hein

Reviewed By: VDG, Plasma, ngraham, hein

Subscribers: plasma-devel, hein, ngraham

Tags: Plasma

Differential Revision: https://phabricator.kde.org/D25925