Allow instances of subclasses of wrapper class to be pattern matched via #deconstruct_keys

[itojum]

Added #deconstruct_keys to the GraphQL::Schema::Wrapper class. This allows pattern matching against List and NonNull, which are subclasses of the Wrapper class.

This allows using pattern matching for concise access to internal elements when dealing with nested structures.

Example:

obj = GraphQL::Schema::List.new(GraphQL::Schema::NonNull.new("Matched!"))
case obj
in GraphQL::Schema::List(of_type: GraphQL::Schema::NonNull(of_type: message))
  p message # => "Matched!"
else
  p "No match"
end

I also referred to the PR that adds #deconstruct_keys to the InputObject.
#5170

[rmosolgo]

Looks good, thanks for this improvement 👍