fix: do not cache models with internal callables by default

This commit ensures that Model's with internal_callables are not cached by default. This is primarily because these Models often fetch real-time data, not stored config data. This change also allows for these models to override this default.

Author: jaredhendrickson13

pfSense-pkg-RESTAPI/files/usr/local/pkg/RESTAPI/Core/Model.inc

@@ -149,7 +149,7 @@ class Model {
      * If set to `true`, this Model will be exempt from any global Model caching mechanisms. This is primarily
      * used for Models that frequently change or are not suitable for caching.
      */
-    public bool $model_cache_exempt = false;
+    public bool $model_cache_exempt;
 
     /**
      * @var ModelSet $related_objects
@@ -341,6 +341,11 @@ class Model {
             );
         }
 
+        # Set the model cache exemption if it was not explicitly defined
+        if (!isset($this->model_cache_exempt)) {
+            $this->model_cache_exempt = (bool) $this->internal_callable;
+        }
+
         # Check for known $options and map them to their Model properties
         $options = $this->set_construct_options($options);