external data: forgot to add the new html provider to the list

Change-Id: I4982cd9213827493ce41c99ddf4048ddbfd08618
Reviewed-on: https://gerrit.libreoffice.org/41337Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

sc/source/ui/dataprovider/dataprovider.cxx

@@ -263,6 +263,7 @@ std::vector<OUString> DataProviderFactory::getDataProviders()
 {
     std::vector<OUString> aDataProviders;
     aDataProviders.push_back("org.libreoffice.calc.csv");
+    aDataProviders.push_back("org.libreoffice.calc.html");
 
     return aDataProviders;
 }