Add Cheer glyph to EuiIcon

[gjones]

Summary

Related to #2813
We're looking to add an icon that communicates an announcement, this is one that our team came up with.

Checklist

• Check against all themes for compatibility in both light and dark modes
• Checked in mobile
• Checked in IE11 and Firefox
• Props have proper autodocs
• Added documentation examples
• Added or updated jest tests
• Checked for breaking changes and labeled appropriately
• Checked for accessibility including keyboard-only and screenreader modes
• A changelog entry exists and is marked appropriately

cc @kaleighflynn

[cchaos]

😎 Nice.

I pulled the icon down and put it onto a pixel grid and it looks like the icon uses several line types (some rounded caps, some not) and there are lines that could be aligned to the pixel grid but aren't. This will make them very fuzzy on non-retina screens. If you need some help adjusting the icon let us know.

[gjones]

If you need some help adjusting the icon let us know.

If possible, that would be great, I'm happy to zoom and go over it or if its quick and easy, and you don't mind, I'm also happy for you to clean it up.

[cchaos]

I'll take a stab for you.

[cchaos]

It is quite difficult to get a rotated triangle with rounded corners to align to the pixel grid. I did the best I could there, but most of the other lines and dots do now align and all use the same rounded corners.

[gjones]

Thanks @cchaos looks great!

[cchaos]

Talked with @gjones about it a bit more and decided to make some changes to the confetti portion to try to remove the carrot likeness.

[cchaos]

LGTM 😉