[Overlay] Use CultureInfo.InvariantCulture for background-color and z-index#4366

vnbaaij merged 2 commits intomicrosoft:devmicrosoft/fluentui-blazor:devfrom

MarvinKlein1508:overlay-invariant-cultureMarvinKlein1508/fluentui-blazor:overlay-invariant-cultureCopy head branch name to clipboard