[NcCounterBubble] RFC: change color theming of default counter

[Antreesy]

Currently, default color scheme for the component makes it visually blend with elements nearby (compared to highlighted and outlined.
In personal discussion, idea comes up to apply a contrast grey fill-color for a default state, to make the component more visible/readable, but distinct from other variants t the same time

P.S. not sure about the color on-active, feels fine to keep the current scheme?

Current	Proposal
background-color: var(--color-primary-element-light)	background-color: var(--color-border-maxcontrast)
color: var(--color-primary-element-light)	color: var(--color-primary-element-text)
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