feat: added ai gradient icons

[agliga]

Fixes #2149

• This PR contains CSS changes
• This PR does not contain CSS changes

Description

• Added support for gradient icons which have nested defs

Notes

Here are the following changes that needed to be done to get this to work

• Pulled out all defs from icons. Added those in an array in the script
• Appended those to the top of the global icons.svg sheet as defs tag
• Now, this would work fine as is, but there is a chrome bug where an external file does not pull in the defs. In order to get around this, we need to embed the SVG file in the top of the docs page. So I added a way to copy the svg file to an html file and then include that in the root of the skin docs. I also added a style to hide it in the top of the page.
• Some other files were modified. There was a typo I fixed in the scripts which had height spelled as heightt.

Screenshots

Checklist

• I verify the build is in a non-broken state

• I verify all changes are within scope of the linked issue

• I regenerated all CSS files under dist folder

• I tested the UI in all supported browsers

• I did a visual regression check of the components impacted by doing a Percy build and approved the build

• I tested the UI in dark mode and RTL mode

• I added/updated/removed Storybook coverage as appropriate

[agliga]

Should be ready for rereview @ArtBlue

[ArtBlue]

Looks great!