Remove GetRecursivelyReferencedUsedFragments and SkipNode

[Shane32]

• The AuthorizationVisitorBase.GetRecursivelyReferencedUsedFragments method has been removed as ValidationContext now provides a overload to GetRecursivelyReferencedFragments which will only return fragments in use by the specified operation.
• The AuthorizationVisitorBase.SkipNode method has been removed as ValidationContext now provides a ShouldIncludeNode method.

See below PR which added both methods in the main project:

• Update GetRecursivelyReferencedFragments to allow retrieving only used fragments graphql-dotnet#3981

Note:

• Unreferenced fragment testing is present within AuthorizationTests.UnusedFragmentsAreIgnored
• Skip/ignore testing is present within AuthorizationTests.SkipInclude