Avoid com.sun.star.container.NoSuchElementException "Active" (3)

Launch Math and notice this kind of logs:
warn:unotools:4125:4125:unotools/source/config/confignode.cxx:444: DBG_UNHANDLED_EXCEPTION
in com::sun::star::uno::Any utl::OConfigurationNode::getNodeValue(const rtl::OUString&) const
type: com.sun.star.container.NoSuchElementException
message: Active
context: configmgr::RootAccess

Change-Id: I4bb1af5caaf53086c243cc8e3a2746ff61cbb869
Reviewed-on: https://gerrit.libreoffice.org/58081
Tested-by: Jenkins
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>

sfx2/source/notebookbar/SfxNotebookBar.cxx

@@ -72,6 +72,9 @@ static OUString lcl_getAppName( vcl::EnumContext::Application eApp )
         case vcl::EnumContext::Application::Draw:
             return OUString( "Draw" );
             break;
+        case vcl::EnumContext::Application::Formula:
+            return OUString( "Formula" );
+            break;
         default:
             return OUString();
             break;