[NTG-context] math font size in captions (and other places)

```Dear all,

I want small caption texts in a document. However, neither of the
following two alternatives work:```
```
%%%%%
%\setupcaptions[style=small]
\setupcaptions[style=\tfx]

\starttext
\placefigure[here][none]{Some math \$x=y\$}{Dummy figure}
\stoptext
%%%%%

In both cases the text is small, but math font is not changed. I can
solve this by doing a \switchtobodyfont in the caption, but I'd like
to do it only once and for all. I guess I have the same problem in all
environments where there is a style= parameter. (For now, I also would
like to set it in \setupmarginblocks.

I've tested this both on mkii and mkiv and with updated (minimal) ConTeXt.

PS Any progress in getting the fourier (utopia+fourier) fonts to work
in the new minimals? I miss that combination of fonts. I did not get
the reason of why it is not included anymore.
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