CSS variable to override the required form input background-image

Hello,

I disagree about the introduction of a new CSS variable which doesn't belong to the Bootstrap API, and it is not ui_suite_bootstrap job to create or extend an API.

Because the color of the required mark is already the one, I suggest to hardcode the initial value:

background-image: url("data:image/svg+xml,%3Csvg height='16' width='16' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='m0 7.562 1.114-3.438c2.565.906 4.43 1.688 5.59 2.35-.306-2.921-.467-4.93-.484-6.027h3.511c-.05 1.597-.234 3.6-.558 6.003 1.664-.838 3.566-1.613 5.714-2.325l1.113 3.437c-2.05.678-4.06 1.131-6.028 1.356.984.856 2.372 2.381 4.166 4.575l-2.906 2.059c-.935-1.274-2.041-3.009-3.316-5.206-1.194 2.275-2.244 4.013-3.147 5.206l-2.856-2.059c1.872-2.307 3.211-3.832 4.017-4.575-2.081-.402-4.058-.856-5.93-1.356' fill='%23dc3545'/%3E%3C/svg%3E%0A");

And add a UI Ssins related hook/event/alter which "listen" the change of the primary color CSS variable and inject an inline CSS code if different from default.

Example if primary === navy:

<style>
.required-mark::after {
background-image: url("data:image/svg+xml,%3Csvg height='16' width='16' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='m0 7.562 1.114-3.438c2.565.906 4.43 1.688 5.59 2.35-.306-2.921-.467-4.93-.484-6.027h3.511c-.05 1.597-.234 3.6-.558 6.003 1.664-.838 3.566-1.613 5.714-2.325l1.113 3.437c-2.05.678-4.06 1.131-6.028 1.356.984.856 2.372 2.381 4.166 4.575l-2.906 2.059c-.935-1.274-2.041-3.009-3.316-5.206-1.194 2.275-2.244 4.013-3.147 5.206l-2.856-2.059c1.872-2.307 3.211-3.832 4.017-4.575-2.081-.402-4.058-.856-5.93-1.356' fill='navy'/%3E%3C/svg%3E%0A");
}
</style>

Reviewed