fix: catch NotFoundError in data vault delete to match spec contract

The spec states "No error if key doesn't exist" but delete() was letting
404 responses bubble up as NotFoundError. Now mirrors the get() pattern
by catching NotFoundError silently, for both sync and async variants.

sdks/implementations/python/src/stack_auth/models/data_vault.py

@@ -34,7 +34,10 @@ class DataVaultStore:
 
     def delete(self, key: str) -> None:
         """Delete a key-value pair. No error if key doesn't exist."""
-        self._client.request("DELETE", f"{self._base_path}/{key}")
+        try:
+            self._client.request("DELETE", f"{self._base_path}/{key}")
+        except NotFoundError:
+            pass
 
     def list_keys(self) -> list[str]:
         """Return all keys in the store."""
@@ -74,7 +77,10 @@ class AsyncDataVaultStore:
 
     async def delete(self, key: str) -> None:
         """Delete a key-value pair. No error if key doesn't exist."""
-        await self._client.request("DELETE", f"{self._base_path}/{key}")
+        try:
+            await self._client.request("DELETE", f"{self._base_path}/{key}")
+        except NotFoundError:
+            pass
 
     async def list_keys(self) -> list[str]:
         """Return all keys in the store."""