[CSS] Update CSS as `-ms-high-constrast` is in the process of being deprecated

[KiddoV]

Bug Report

Please do not use -ms-high-constrast in CSS any more since it will be deprecated.
See:
https://blogs.windows.com/msedgedev/2024/04/29/deprecating-ms-high-contrast/

Currently my console has a lot of this annoying warning.

[Deprecation] -ms-high-constrast is in the process of being deprecated. Please see https://blogs.windows.com/msedgedev/2024/04/29/deprecating-ms-high-contrast/ for tips on updating to the new Forced Colors Mode standard.

Screenshot (if possible)

[lubber-de]

This setting is only used (3 times in total) to detect IE11 via

@media all and (-ms-high-contrast: none) {
/* IE 11 specific code*/
}

All IE11 related code will be removed in 2.10 as decided by the community

if you want to have it removed earlier, change the LESS variable

Fomantic-UI/src/themes/default/globals/site.variables

Line 6 in c48cd9d

@supportIE: true;

to

@supportIE: false;

and rebuild Fomantic.

[KiddoV]

Since I use FUI via NPM, I will wait for v2.10 then. Thanks!

[lubber-de]

Fixed/Removed by #3183