label whitespaces no more

[Jürgen Spitzmüller]

Am Sonntag, dem 18.05.2025 um 00:23 +1200 schrieb Igor:
> I think secref has been already pre-defined by refstyle, but sssref
> wasn't, hence the above definition is used and leads to the error.

This is fixed for LyX 2.5. Too much to backport for LyX 2.4.

As Danie wrote, this is due to the way we define those fallback
commands for unknown prefixes.

-- 
Jürgen