Update python/semantic_kernel/functions/kernel_function.py

For enable deep copy

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: nimanikoo

python/semantic_kernel/functions/kernel_function.py

@@ -388,9 +388,7 @@ def function_copy(self, plugin_name: str | None = None) -> "KernelFunction":
             KernelFunction: The copied function.
         """
         cop: KernelFunction = copy(self)
-        # Only copy metadata if we need to modify plugin_name
-        if plugin_name and plugin_name != self.metadata.plugin_name:
-            cop.metadata = self.metadata.model_copy()  # Shallow copy via Pydantic
+            cop.metadata = self.metadata.model_copy(update={"plugin_name": plugin_name}, deep=True)
             cop.metadata.plugin_name = plugin_name
         else:
             # Reuse reference when no modification needed (safe as metadata is immutable in practice)