qt: Remove an obscure option no-one cares about

Remove the "Display addresses" setting checkbox. It doesn't do what
the tooltip says, and seems kind of pointless in any case.

Fixes #4580.

src/qt/optionsdialog.cpp

@@ -185,7 +185,6 @@ void OptionsDialog::setMapper()
     /* Display */
     mapper->addMapping(ui->lang, OptionsModel::Language);
     mapper->addMapping(ui->unit, OptionsModel::DisplayUnit);
-    mapper->addMapping(ui->displayAddresses, OptionsModel::DisplayAddresses);
     mapper->addMapping(ui->thirdPartyTxUrls, OptionsModel::ThirdPartyTxUrls);
 }