fix(forms): Remove unnecessary prefill_source logic

Eliminates redundant `prefill_source` logic from ACL forms. Simplifies
conditions for resetting `source` and `destination` fields during
initialization, improving code clarity and maintainability.

Author: pheus

netbox_acls/forms/models.py

@@ -579,10 +579,6 @@ def __init__(self, *args, **kwargs) -> None:
             # Initialize the source object field
             initial["source"] = instance.source
 
-        # Check if "comments" is absent, indicating a request with custom
-        # GET parameters for prefilling of the form field "source".
-        prefill_source = "comments" not in initial
-
         kwargs["initial"] = initial
 
         super().__init__(*args, **kwargs)
@@ -602,7 +598,7 @@ def __init__(self, *args, **kwargs) -> None:
                 pass
 
             # Clears the source field if the selected type changes
-            if self.instance and source_type_id != self.instance.source_type_id and not prefill_source:
+            if self.instance and self.instance.pk and source_type_id != self.instance.source_type_id:
                 self.initial["source"] = None
 
     def clean(self):
@@ -744,10 +740,6 @@ def __init__(self, *args, **kwargs) -> None:
             # Initialize the destination object field
             initial["destination"] = instance.destination
 
-        # Check if "comments" is absent, indicating a request with custom
-        # GET parameters for prefilling of the form field "source".
-        prefill_source = "comments" not in initial
-
         kwargs["initial"] = initial
 
         super().__init__(*args, **kwargs)
@@ -768,7 +760,7 @@ def __init__(self, *args, **kwargs) -> None:
                 pass
 
             # Clears the source field if the selected type changes
-            if self.instance and source_type_id != self.instance.source_type_id and not prefill_source:
+            if self.instance and self.instance.pk and source_type_id != self.instance.source_type_id:
                 self.initial["source"] = None
 
         # Destination
@@ -787,7 +779,7 @@ def __init__(self, *args, **kwargs) -> None:
                 pass
 
             # Clears the destination field if the selected type changes
-            if self.instance and destination_type_id != self.instance.destination_type_id and not prefill_source:
+            if self.instance and self.instance.pk and destination_type_id != self.instance.destination_type_id:
                 self.initial["destination"] = None
 
     def clean(self):