Remove read_instance_statistics policy

As Cohorts and DevOps Report were previously under
instance statistics and available to admin or
or everybody that policy made sense.
Currently Cohorts and DevOps Report are
under Admin panel, therefore that policy is no
longer needed.

app/helpers/dashboard_helper.rb

@@ -58,10 +58,6 @@ module DashboardHelper
       links += [:activity, :milestones]
     end
 
-    if can?(current_user, :read_instance_statistics)
-      links << :analytics
-    end
-
     links
   end
 end

app/helpers/nav_helper.rb

@@ -47,7 +47,7 @@ module NavHelper
   end
 
   def has_extra_nav_icons?
-    Gitlab::Sherlock.enabled? || can?(current_user, :read_instance_statistics) || current_user.admin?
+    Gitlab::Sherlock.enabled? || current_user.admin?
   end
 
   def page_has_markdown?

app/policies/global_policy.rb

@@ -98,7 +98,6 @@ class GlobalPolicy < BasePolicy
   rule { admin }.policy do
     enable :read_custom_attribute
     enable :update_custom_attribute
-    enable :read_instance_statistics
   end
 
   # We can't use `read_statistics` because the user may have different permissions for different projects

ee/spec/helpers/ee/dashboard_helper_spec.rb

@@ -10,28 +10,6 @@ RSpec.describe DashboardHelper, type: :helper do
       allow(helper).to receive(:current_user).and_return(user)
     end
 
-    describe 'analytics' do
-      context 'and the user has no access to instance statistics features' do
-        before do
-          stub_user_permissions_for(:analytics, false)
-        end
-
-        it 'does not include analytics' do
-          expect(helper.dashboard_nav_links).not_to include(:analytics)
-        end
-      end
-
-      context 'and the user has access to instance statistics features' do
-        before do
-          stub_user_permissions_for(:analytics, true)
-        end
-
-        it 'does include analytics' do
-          expect(helper.dashboard_nav_links).to include(:analytics)
-        end
-      end
-    end
-
     describe 'operations dashboard link' do
       context 'when the feature is available on the license' do
         context 'and the user is authenticated' do
@@ -160,11 +138,9 @@ RSpec.describe DashboardHelper, type: :helper do
     def stub_user_permissions_for(feature, enabled)
       allow(helper).to receive(:can?).with(user, :read_cross_project).and_return(false)
 
-      can_read_instance_statistics = enabled && feature == :analytics
       can_read_operations_dashboard = enabled && feature == :operations
       can_read_instance_security_dashboard = enabled && feature == :security
 
-      allow(helper).to receive(:can?).with(user, :read_instance_statistics).and_return(can_read_instance_statistics)
       allow(helper).to receive(:can?).with(user, :read_operations_dashboard).and_return(can_read_operations_dashboard)
       allow_next_instance_of(InstanceSecurityDashboard) do |dashboard|
         allow(helper).to(

rubocop/cop/avoid_route_redirect_leading_slash.rb

@@ -7,10 +7,10 @@ module RuboCop
     #
     # @example
     #   # bad
-    #   root to: redirect('/-/instance_statistics/dev_ops_report')
+    #   root to: redirect('/-/autocomplete/users')
     #
     #   # good
-    #   root to: redirect('-/instance_statistics/dev_ops_report')
+    #   root to: redirect('-/autocomplete/users')
     #
 
     class AvoidRouteRedirectLeadingSlash < RuboCop::Cop::Cop

spec/policies/global_policy_spec.rb

@@ -370,24 +370,6 @@ RSpec.describe GlobalPolicy do
     end
   end
 
-  describe 'read instance statistics' do
-    context 'regular user' do
-      it { is_expected.to be_disallowed(:read_instance_statistics) }
-    end
-
-    context 'admin', :enable_admin_mode do
-      let(:current_user) { create(:admin) }
-
-      it { is_expected.to be_allowed(:read_instance_statistics) }
-    end
-
-    context 'anonymous' do
-      let(:current_user) { nil }
-
-      it { is_expected.not_to be_allowed(:read_instance_statistics) }
-    end
-  end
-
   describe 'slash commands' do
     context 'regular user' do
       it { is_expected.to be_allowed(:use_slash_commands) }