Remove admin_user

In ManageIQ#17444 and related PRs
References to generic admin_user and used request_admin_user/others

This removes the method for good

app/models/miq_user_role.rb

@@ -116,8 +116,6 @@ def report_admin_user?
     allows?(:identifier => MiqProductFeature::REPORT_ADMIN_FEATURE)
   end
 
-  alias admin_user? report_admin_user?
-
   def request_admin_user?
     allows?(:identifier => MiqProductFeature::REQUEST_ADMIN_FEATURE)
   end

app/models/user.rb

@@ -33,7 +33,7 @@ class User < ApplicationRecord
 
   delegate   :miq_user_role, :current_tenant, :get_filters, :has_filters?, :get_managed_filters, :get_belongsto_filters,
              :to => :current_group, :allow_nil => true
-  delegate   :super_admin_user?, :admin_user?, :self_service?, :limited_self_service?, :report_admin_user?,
+  delegate   :super_admin_user?, :request_admin_user?, :self_service?, :limited_self_service?, :report_admin_user?,
              :to => :miq_user_role, :allow_nil => true
 
   validates_presence_of   :name, :userid

spec/models/miq_user_role_spec.rb

@@ -192,19 +192,16 @@
     end
   end
 
-  describe "#admin_user?", "#report_admin_user?" do
+  describe "#report_admin_user?" do
     it "detects super admin" do
-      expect(super_admin_role).to be_admin_user
       expect(super_admin_role).to be_report_admin_user
     end
 
     it "detects admin" do
-      expect(report_admin_role).to be_admin_user
       expect(report_admin_role).to be_report_admin_user
     end
 
     it "detects non-admin" do
-      expect(regular_role).not_to be_admin_user
       expect(regular_role).not_to be_report_admin_user
     end
   end

spec/models/user_spec.rb

@@ -143,18 +143,6 @@
         expect(user.super_admin_user?).to be_falsey
       end
     end
-
-    describe "#admin_user?" do
-      let(:role_name) { "administrator" }
-
-      it "should check Admin Roles" do
-        expect(user.admin_user?).to be_truthy
-        expect(user.super_admin_user?).to be_falsey
-
-        user.current_group = nil
-        expect(user.admin_user?).to be_falsey
-      end
-    end
   end
 
   context "#authorize_ldap" do