Fixes email invites being case senstive

Fixes a bug when accepting an email invite it would
require both the invited email and the users email
to match case.

Changelog: fixed

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/338022

app/controllers/invites_controller.rb

@@ -52,7 +52,7 @@ class InvitesController < ApplicationController
   end
 
   def current_user_matches_invite?
-    current_user.verified_emails.include?(@member.invite_email)
+    current_user.verified_email?(@member.invite_email)
   end
 
   def member?

spec/features/invites_spec.rb

@@ -103,6 +103,20 @@ RSpec.describe 'Group or Project invitations', :aggregate_failures do
               expect(page).to have_content('You are already a member of this group.')
             end
           end
+
+          context 'when email case doesnt match', :js do
+            let(:invite_email) { 'User@example.com' }
+            let(:user) { create(:user, email: 'user@example.com') }
+
+            before do
+              sign_in(user)
+              visit invite_path(group_invite.raw_invite_token)
+            end
+
+            it 'accepts invite' do
+              expect(page).to have_content('You have been granted Developer access to group Owned.')
+            end
+          end
         end
 
         context 'when declining the invitation from invitation reminder email' do