Rename test file and directory

Diretory
Before: issues
After: issues_weight

File
Before: issues_weights_spec.rb
After: issue_weight_visualization_spec.rb

Also, update test suite description.

qa/qa/specs/features/ee/browser_ui/2_plan/issues/issues_weights_spec.rb → qa/qa/specs/features/ee/browser_ui/2_plan/issues_weight/issue_weight_visualization_spec.rb

@@ -2,7 +2,7 @@
 
 module QA
   context 'Plan' do
-    describe 'Issues weights' do
+    describe 'Issues weight visualization' do
       before do
         Runtime::Browser.visit(:gitlab, Page::Main::Login)
         Page::Main::Login.perform(&:sign_in_using_credentials)