Refactor Project Member policy

app/policies/project_member_policy.rb

@@ -3,13 +3,16 @@
 class ProjectMemberPolicy < BasePolicy
   delegate { @subject.project }
 
-  condition(:target_is_owner, scope: :subject) { @subject.user == @subject.project.owner }
+  condition(:target_is_holder_of_the_personal_namespace, scope: :subject) do
+    @subject.project.personal_namespace_holder?(@subject.user)
+  end
+
   condition(:target_is_self) { @user && @subject.user == @user }
   condition(:project_bot) { @subject.user&.project_bot? }
 
   rule { anonymous }.prevent_all
 
-  rule { target_is_owner }.policy do
+  rule { target_is_holder_of_the_personal_namespace }.policy do
     prevent :update_project_member
     prevent :destroy_project_member
   end

spec/policies/project_member_policy_spec.rb

@@ -23,9 +23,9 @@ RSpec.describe ProjectMemberPolicy do
     it { is_expected.not_to be_allowed(:destroy_project_bot_member) }
   end
 
-  context 'when user is project owner' do
-    let(:member_user) { project.first_owner }
-    let(:member) { project.members.find_by!(user: member_user) }
+  context 'when user is the holder of personal namespace in which the project resides' do
+    let(:namespace_holder) { project.namespace.owner }
+    let(:member) { project.members.find_by!(user: namespace_holder) }
 
     it { is_expected.to be_allowed(:read_project) }
     it { is_expected.to be_disallowed(:update_project_member) }