Remove user_search_secondary_email feature flag

User searching now also does an exact string match through the
secondary emails table, previously happened under a feature flag.

app/models/user.rb

@@ -591,13 +591,7 @@ class User < ApplicationRecord
 
       sanitized_order_sql = Arel.sql(sanitize_sql_array([order, query: query]))
 
-      search_query = if Feature.enabled?(:user_search_secondary_email)
-                       search_with_secondary_emails(query)
-                     else
-                       search_without_secondary_emails(query)
-                     end
-
-      search_query.reorder(sanitized_order_sql, :name)
+      search_with_secondary_emails(query).reorder(sanitized_order_sql, :name)
     end
 
     # Limits the result set to users _not_ in the given query/list of IDs.

changelogs/unreleased/cat-remove-user-secondary-email-ff.yml

+---
+title: Remove user_search_secondary_email feature flag
+merge_request: 49312
+author:
+type: changed

config/feature_flags/development/user_search_secondary_email.yml

----
-name: user_search_secondary_email
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/47587
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/282137
-milestone: '13.7'
-type: development
-group: group::access
-default_enabled: false

spec/models/user_spec.rb

@@ -2068,7 +2068,6 @@ RSpec.describe User do
     end
 
     describe 'secondary email matching' do
-      context 'feature flag :user_search_secondary_email is enabled' do
       it 'returns users with a matching secondary email' do
         expect(described_class.search(email.email)).to include(email.user)
       end
@@ -2082,21 +2081,6 @@ RSpec.describe User do
       end
     end
 
-      context 'feature flag :user_search_secondary_email is disabled' do
-        before do
-          stub_feature_flags(user_search_secondary_email: false)
-        end
-
-        it 'does not return users with a matching secondary email' do
-          expect(described_class.search(email.email)).not_to include(email.user)
-        end
-
-        it 'does not return users with a matching part of secondary email' do
-          expect(described_class.search(email.email[1...-1])).to be_empty
-        end
-      end
-    end
-
     describe 'username matching' do
       it 'returns users with a matching username' do
         expect(described_class.search(user.username)).to eq([user, user2])