fix SAL_WARN when instantiating Thesaurus

Before
    commit 3fbadfa1ad
    lingucomponent: create instances with uno constructors
Thesaurus was constructed but Thesaurus::initialize was NOT being called
from GetAvailLocales.

However, we have some code marked "HACK" in
   cppuhelper/source/servicemanager.cxx
i.e.
   ServiceManager....::createInstanceWithArguments
which DOES call initialize.

And we have code in GetAvailLocales which passes what Thesuarus
considers an invalid number of arguments, because all the other similar
services DO take 2 args (even though they don't use the second arg!)

So we have a bunch of temporary hack and backwards compat stuff
interacting, causing a SAL_WARN.

So make Thesauras::initialize a little more tolerant, which means we're
now initialising it, which is a change in behaviour, so if this commit
comes up a regression, we will need find another warn to stop the
warning.

Change-Id: I60e0ed1bd2d4fbccbc539b5536aba055a7dfc6c4
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/99039
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

lingucomponent/source/thesaurus/libnth/nthesimp.cxx

@@ -466,10 +466,13 @@ void SAL_CALL Thesaurus::initialize( const Sequence< Any >& rArguments )
         return;
 
     sal_Int32 nLen = rArguments.getLength();
-    if (1 == nLen)
+    // Accept one of two args so we can be compatible with the call site in GetAvailLocales()
+    // linguistic module
+    if (1 == nLen || 2 == nLen)
     {
         Reference< XLinguProperties >   xPropSet;
         rArguments.getConstArray()[0] >>= xPropSet;
+        assert(xPropSet);
 
         //! Pointer allows for access of the non-UNO functions.
         //! And the reference to the UNO-functions while increasing

linguistic/source/lngsvcmgr.cxx

@@ -73,8 +73,7 @@ static uno::Sequence< lang::Locale > GetAvailLocales(
     {
         std::set< LanguageType > aLanguages;
 
-        //! since we're going to create one-instance services we have to
-        //! supply their arguments even if we would not need them here...
+        // All of these services only use one arg, but need two args for compat reasons
         uno::Sequence< uno::Any > aArgs(2);
         aArgs.getArray()[0] <<= GetLinguProperties();