Improve design for Collapsible Admonitions

[smeragoel]

Link to component

While working on the focus state for collapsible admonitions, @trallard noticed that we currently have two components that look and behave almost the same, but differ in implementation.

1. Dropdowns
2. Toggle Buttons

We decided to unify the properties of these two components to create a better design for collapsible admonitions which included: hover interactions and more intutive arrow directions from (1) and Click to show button from (2).

You can find the link for the component here: Figma link for component

Here's a video for the expected functionality:

Collapsible.Admonitions.mp4