Address Rubocop warnings and CodeClimate issues

lib/rubocop/cop/rspec/let_setup.rb

@@ -51,16 +51,11 @@ def unused_let_bang(node)
         end
 
         def child_let_bang(block_node)
-          return unless block_node.body
+          return unless block_node.body&.begin_type?
 
-          body = block_node.body
-
-          if body.begin_type?
-            body.each_child_node(:block) do |child|
-              if result = let_bang(child)
-                yield result
-              end
-            end
+          block_node.body.each_child_node(:block) do |child|
+            node_with_name = let_bang(child)
+            yield node_with_name if node_with_name
           end
         end
       end