Set launch_template.ami_id attrs to private (#2842)

Author: dcmcand

src/_nebari/stages/infrastructure/__init__.py

@@ -8,7 +8,7 @@
 import tempfile
 from typing import Annotated, Any, Dict, List, Literal, Optional, Tuple, Type, Union
 
-from pydantic import ConfigDict, Field, field_validator, model_validator
+from pydantic import ConfigDict, Field, PrivateAttr, field_validator, model_validator
 
 from _nebari import constants
 from _nebari.provider import terraform
@@ -136,7 +136,7 @@ class AWSAmiTypes(str, enum.Enum):
 
 class AWSNodeLaunchTemplate(schema.Base):
     pre_bootstrap_command: Optional[str] = None
-    ami_id: Optional[str] = None
+    _ami_id: Optional[str] = PrivateAttr(default=None)
 
 
 class AWSNodeGroupInputVars(schema.Base):
@@ -155,7 +155,7 @@ class AWSNodeGroupInputVars(schema.Base):
 def construct_aws_ami_type(gpu_enabled: bool, launch_template: AWSNodeLaunchTemplate):
     """Construct the AWS AMI type based on the provided parameters."""
 
-    if launch_template and launch_template.ami_id:
+    if launch_template and launch_template._ami_id:
         return "CUSTOM"
 
     if gpu_enabled: