Use a separate icon factory for app badge icons

We were reusing the same BubbleIconFactory for bubble icons and app
badge icons. BubbleIconFactory extends BaseIconFactory and resizes all
created icons to one size. BubbleIconFactory was configured to resize
icons to the size of bubbles as defined by bubble_size dimensions,
currently at 60dp.
Badge icon size is defined by bubble_badge_size and is currently at
24dp. Using the same BubbleIconFactory for both icons meant that we were
resizing all badge icons to be the same size as bubbles, at first. And
then, when actually using them, sizing them down again.
This change introduces a separate BubbleBadgeIconFactory with relevant
code moved from BubbleIconFactory. And mainly, it defines the icon size
as the size of the badge. Avoiding resizing.

Test: visually verified that the badge icon looks the same
Bug: 189173831
Change-Id: Ie032bbc15eb0fd3e78636796bafb05149e262850