feat: Add the ability for a super admin to define account limits (#3946)

Fixes: #3773

enterprise/app/models/enterprise/account.rb

@@ -1,8 +1,8 @@
 module Enterprise::Account
   def usage_limits
     {
-      agents: get_limits(:agents),
-      inboxes: get_limits(:inboxes)
+      agents: get_limits(:agents).to_i,
+      inboxes: get_limits(:inboxes).to_i
     }
   end
 
@@ -12,4 +12,21 @@ module Enterprise::Account
     config_name = "ACCOUNT_#{limit_name.to_s.upcase}_LIMIT"
     self[:limits][limit_name.to_s] || GlobalConfig.get(config_name)[config_name] || ChatwootApp.max_limit
   end
+
+  def validate_limit_keys
+    errors.add(:limits, ': Invalid data') unless self[:limits].is_a? Hash
+    self[:limits] = {} if self[:limits].blank?
+
+    limit_schema = {
+      'type' => 'object',
+      'properties' => {
+        'inboxes' => { 'type': 'number' },
+        'agents' => { 'type': 'number' }
+      },
+      'required' => [],
+      'additionalProperties' => false
+    }
+
+    errors.add(:limits, ': Invalid data') unless JSONSchemer.schema(limit_schema).valid?(self[:limits])
+  end
 end