wallet2: fix out of sync account tag cache

This would cause crashes when trying to tag an account that was
just created

src/wallet/wallet2.cpp

@@ -940,6 +940,7 @@ void wallet2::expand_subaddresses(const cryptonote::subaddress_index& index)
     }
     m_subaddress_labels.resize(index.major + 1, {"Untitled account"});
     m_subaddress_labels[index.major].resize(index.minor + 1);
+    get_account_tags();
   }
   else if (m_subaddress_labels[index.major].size() <= index.minor)
   {