As of my understanding you are unable to find configuration blade in logic App .You are facing this issue because your searching configuration blade in Consumption logic App.
As shown in below Consumption logic App's menu there is no Configuration option.

Open your Standard logic App, in your Standard logic app's menu, under settings you can find Configuration as shown in below image.

To resolve key vault reference error configure your created keyvault in standard logicapp as shown in below image then you can able to find keyvault reference by following reference link
