fix(etsy): remove nameof usage to source settings

After Binding to the EtsyAuthenticationOptions Type instead of each value as section name the actual value we got was by using `nameof(EtsyAuthenticationDefaults.DisplayName)` "DisplayName" and not "Etsy", so this couldn't work with this applyed. Removing the nameof makes it bind again properly

Author: DevTKSS

samples/Mvc.Client/Startup.cs

@@ -66,7 +66,7 @@ public void ConfigureServices(IServiceCollection services)
 
         .AddEtsy(options =>
         {
-            var etsySection = configuration.GetSection(nameof(EtsyAuthenticationDefaults.DisplayName)).Get<EtsyAuthenticationOptions>();
+            var etsySection = configuration.GetSection(EtsyAuthenticationDefaults.DisplayName).Get<EtsyAuthenticationOptions>();
             if (etsySection is not null)
             {
                 options.ClientId = etsySection.ClientId;