No default mutable object in dlt_dagster_translator argument to dlt_a…

…ssets (#21350)

## Summary & Motivation

Similar to #21340, but for `dlt_assets`. Per https://docs.python-guide.org/writing/gotchas/ you should not set a default parameter to an object instance.

## How I Tested These Changes

BK

python_modules/libraries/dagster-embedded-elt/dagster_embedded_elt/dlt/asset_decorator.py

@@ -3,6 +3,7 @@
 from dagster import (
     AssetsDefinition,
     AssetSpec,
+    _check as check,
     multi_asset,
 )
 from dlt.extract.source import DltSource
@@ -18,7 +19,7 @@ def dlt_assets(
     dlt_pipeline: Pipeline,
     name: Optional[str] = None,
     group_name: Optional[str] = None,
-    dlt_dagster_translator: DagsterDltTranslator = DagsterDltTranslator(),
+    dlt_dagster_translator: Optional[DagsterDltTranslator] = None,
 ) -> Callable[[Callable[..., Any]], AssetsDefinition]:
     """Asset Factory for using data load tool (dlt).
 
@@ -76,6 +77,10 @@ def github_reactions_dagster_assets(context: AssetExecutionContext, dlt: DltDags
                 yield from dlt.run(context=context)
 
     """
+    dlt_dagster_translator = (
+        check.opt_inst_param(dlt_dagster_translator, "dlt_dagster_translator", DagsterDltTranslator)
+        or DagsterDltTranslator()
+    )
     return multi_asset(
         name=name,
         group_name=group_name,