Class properties in several components filter out classes with colons

[codymullins]

Class properties seem to filter out class names with colons. This is on v5.

The following WORKS:

<FluentAnchorButton Href="/" Appearance="ButtonAppearance.Subtle"
                    Color="var(--colorNeutralForegroundOnBrand)"
                    BackgroundColor="var(--colorBrandBackgroundHover)"
                    Class="hidden md-block">
    Playground
</FluentAnchorButton>

The following DOES NOT WORK, only the hidden will be applied.

<FluentAnchorButton Href="/" Appearance="ButtonAppearance.Subtle"
                    Color="var(--colorNeutralForegroundOnBrand)"
                    BackgroundColor="var(--colorBrandBackgroundHover)"
                    Class="hidden md:block">
    Playground
</FluentAnchorButton>

[dvoituron]

That is an existing discussion.
We try to respect the characters/symbols allowed within the CSS class selectors
https://stackoverflow.com/questions/448981/which-characters-are-valid-in-css-class-names-selectors

So, we validate CSS class using this regex: "^-?[_a-zA-Z]+[_a-zA-Z0-9-]*$".

However, you can bypass this validation by setting this flag:

CssBuilder.ValidateClassNames = false;