Fix: Changing default livery did not propagate to group liveries.

#11614 attempted to address this but did not handle 2CC properly, and changes to the default livery were not handled.

src/company_func.h

@@ -24,6 +24,7 @@ void ShowBuyCompanyDialog(CompanyID company, bool hostile_takeover);
 void CompanyAdminUpdate(const Company *company);
 void CompanyAdminBankrupt(CompanyID company_id);
 void UpdateLandscapingLimits();
+void UpdateCompanyLiveries(Company *c);
 
 bool CheckCompanyHasMoney(CommandCost &cost);
 void SubtractMoneyFromCompany(const CommandCost& cost);