Move spec to Plan and improve description

qa/qa/specs/features/browser_ui/1_manage/mail/trigger_mail_notification_spec.rb → qa/qa/specs/features/browser_ui/2_plan/email/trigger_email_notification_spec.rb

 # frozen_string_literal: true
 
 module QA
-  context 'Manage', :orchestrated, :smtp do
-    describe 'mail notification' do
+  context 'Plan', :orchestrated, :smtp do
+    describe 'Email Notification' do
       let(:user) do
         Resource::User.fabricate_or_use(Runtime::Env.gitlab_qa_username_1, Runtime::Env.gitlab_qa_password_1)
       end
@@ -17,7 +17,7 @@ module QA
         Flow::Login.sign_in
       end
 
-      it 'user receives email for project invitation' do
+      it 'is received by a user for project invitation' do
         Flow::Project.add_member(project: project, username: user.username)
 
         expect(page).to have_content(/@#{user.username}(\n| )?Given access/)