chore: Allow Contextual Menu Component to be positioned optimally [WD-10977]

[Kxiru]

… vertically

Done

• Added a scss file for Contextual Menu
• Implemented initial logic by @mas-who to vertically position the Menu optimally based on the viewport height.
• Then transferred this logic from AdjustVerticalHeight function in Contextual Menu, to updateVerticalPosition function in ContextualMenuDropdown.tsx such that the menu may be adjusted according to both the container height and the viewport height.

QA

Storybook

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yarn start

QA in your project

from react-components run:

yarn build
npm pack

Install the resulting tarball in your project with:

yarn add <path-to-tarball>

Percy steps

N/A

Fixes

• Contextual Menu dropdown now displays "upwards" if there is not enough space downwards.