Option "tight-spacing" fails with tex4ht

[josephwright]

Raised in https://tex.stackexchange.com/questions/707485/how-to-use-make4ht-for-threeparttable-with-siunitx-to-make-an-odt, needs analysis and either the option disabling or a stronger fix

[josephwright]

MWE:

\documentclass{article}
\usepackage{siunitx}
\sisetup{mode = text, uncertainty-mode = separate}
\begin{document}
\num[tight-spacing]{3.25(2)}
\end{document}

This needs the separate uncertainty, and we need tight-spacing after the start of the document so that the current tex4ht patch is bypassed. An exponent without an uncertainty does not raise the issue.