Ability to style flipper buttons in suggested actions

Is your feature request related to a problem?

The flipper button in suggested actions cannot be fully styled:

• Button chrome (border, radius, etc.)
• Icon

Describe the suggestion or request in detail

Ability to style more aspect of the flipper button in suggested actions.

After discussion with designer:

• Suggested action buttons appearance: rectangular or circular
• Suggested action buttons color mode (per button): white, primary, accent, ghost
  • Because this could be done on a per button basis, probably set in the activity, rather than set in style options
  • Is it okay/possible to set style options via channel data?
• Flipper buttons appearance: rectangular or circular
• Flipper buttons color mode: light mode, or dark mode (today)
• Item alignment: icon + text, text + icon, text-only, icon-only
• Size: small, medium, large
• Layout style: horizontal, bubbles (vertical as reply bubbles)

Describe alternatives you have considered

Style through CSS is not trivial and could break from time to time due to DOM change (unless via CSS insertion point or custom CSS properties).

Additional context

Related to AzDO #3653452.

No response

Start by locating the suggested-actions flipper-button implementation and its styling options; the issue names no files or tests. Review the proposed appearance, color mode, alignment, size, and layout requirements, including whether per-button values belong in activity or channel data. Done means these options are supported without relying on fragile DOM-specific CSS.