chore: Validation for purchased pricing_plan_quantity (#8809)

- Add validations based on purchased pricing_plan_quantity
- Modify the Dashboard to support the new error message

spec/enterprise/models/user_spec.rb

@@ -5,6 +5,44 @@ require 'rails_helper'
 RSpec.describe User do
   let(:user) { create(:user) }
 
+  describe 'before validation for pricing plans' do
+    let(:new_user) { build(:user) }
+
+    context 'when pricing plan is not premium' do
+      before do
+        allow(ChatwootHub).to receive(:pricing_plan).and_return('community')
+        allow(ChatwootHub).to receive(:pricing_plan_quantity).and_return(0)
+      end
+
+      it 'does not add an error to the user' do
+        new_user.valid?
+        expect(new_user.errors[:base]).to be_empty
+      end
+    end
+
+    context 'when pricing plan is premium' do
+      before do
+        allow(ChatwootHub).to receive(:pricing_plan).and_return('premium')
+      end
+
+      context 'when the user limit is reached' do
+        it 'adds an error to the user' do
+          allow(ChatwootHub).to receive(:pricing_plan_quantity).and_return(1)
+          user.valid?
+          expect(user.errors[:base]).to include('User limit reached. Please purchase more licenses from super admin')
+        end
+      end
+
+      context 'when the user limit is not reached' do
+        it 'does not add an error to the user' do
+          allow(ChatwootHub).to receive(:pricing_plan_quantity).and_return(2)
+          user.valid?
+          expect(user.errors[:base]).to be_empty
+        end
+      end
+    end
+  end
+
   describe 'audit log' do
     context 'when user is created' do
       it 'has no associated audit log created' do