Fix signatures sometimes not saving (2)

app/src/main/java/eu/faircode/email/FragmentIdentity.java

@@ -1064,6 +1064,7 @@ public class FragmentIdentity extends FragmentBase {
                     grpAdvanced.setVisibility(savedInstanceState.getInt("fair:advanced"));
                     auth = savedInstanceState.getInt("fair:auth");
                     provider = savedInstanceState.getString("fair:authprovider");
+                    if (signature == null)
                         signature = savedInstanceState.getString("fair:html");
                 }