Remove endpoint param from provider spec

Author: mullermp

gems/smithy/lib/smithy/templates/client/endpoint_provider_spec.erb

@@ -32,7 +32,6 @@ module <%= module_name %>
       it 'produces the correct output from the client when calling <%= operation_input.operation_name %>' do
         client = Client.new(
           stub_responses: true,
-          endpoint: nil,
           endpoint_provider: subject,
 <% operation_input.client_params.each do |p| -%>
           <%= p.param %>: <%= p.value %>,