[com.google.fonts/check/varfont/unsupported_axes] should be downgraded to WARN

[kontur]

The check and testing outlined in #3108 is very valid, and hopefully urges browser vendors on to improve their implementations.

However, a FAIL for this seems to go completely overboard. All browsers, even in the very early date of the check in 2020, support the font-variation-settings use of the ital axis. A font with ital axis is perfectly valid and working, and the axis is a registered axis. Only a subset of browser CSS keyword use of such a font is misbehaving.

If GF wants to enforce this as FAIL then make it vendor specific. Since this is in the Universal profile, I think the FAIL is way too harsh and should be a WARN at most. I think it makes sense to draw font vendor attention to this, but outright advocating to not use the ital axis at all seems backwards, especially as the issue is application specific and not universal.