Adding a new layer source without an attribution causes an error

[RobQuincey-DC]

When creating a new layer source from the wizard, if you try to add it without choosing an attributon, an error is thrown

at AspNetCoreGeneratedDocument.Views_ManagementLayerWizard_CreateSource+<ExecuteAsync>d__29.MoveNext (GIFrameworkMaps.Web, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null: D:\a\GIFramework-Maps\GIFramework-Maps\GIFrameworkMaps.Web\Views\ManagementLayerWizard\CreateSource.cshtml:105)

It then redirects to the version not found page, which is additionally very wrong error handling!