fix: constantize model_class on runtime

lib/avo/concerns/model_class_constantized.rb

@@ -6,11 +6,16 @@ module ModelClassConstantized
       class_methods do
         # Cast the model class to a constantized version and memoize it like that
         def model_class=(value)
-          @model_class = case value
+          @model_class = value
+        end
+
+        # Cast the model class to a constantized version
+        def constantized_model_class
+          @constantized_model_class ||= case @model_class
           when Class
-            value
+            @model_class
           when String, Symbol
-            value.to_s.safe_constantize
+            @model_class.to_s.safe_constantize
           else
             raise ArgumentError.new "Failed to find a proper model class for #{self}"
           end

lib/avo/resources/base.rb

@@ -143,7 +143,7 @@ def get_model_by_name(model_name)
         # where we figure out the model class from the record
         def model_class(record_class: nil)
           # get the model class off of the static property
-          return @model_class if @model_class.present?
+          return constantized_model_class if @model_class.present?
 
           # get the model class off of the record for STI models
           return record_class if record_class.present?