[dagster-sigma] Mark get_asset_key as deprecated in DagsterSigmaTrans…

…lator (#26036)

## Summary & Motivation

Like #26028 but for Sigma

## Changelog

[dagster-sigma] `DagsterSigmaTranslator.get_asset_key` is deprecated in
favor of `DagsterSigmaTranslator.get_asset_spec().key`

python_modules/libraries/dagster-sigma/dagster_sigma/translator.py

@@ -2,6 +2,7 @@
 from typing import AbstractSet, Any, Dict, List, Optional, Union
 
 from dagster import AssetKey, AssetSpec, MetadataValue, TableSchema
+from dagster._annotations import deprecated
 from dagster._core.definitions.metadata.metadata_set import TableMetadataSet
 from dagster._core.definitions.metadata.table import TableColumn
 from dagster._record import record
@@ -97,6 +98,10 @@ def __init__(self, context: SigmaOrganizationData):
     def organization_data(self) -> SigmaOrganizationData:
         return self._context
 
+    @deprecated(
+        breaking_version="1.10",
+        additional_warn_text="Use `DagsterSigmaTranslator.get_asset_spec(...).key` instead",
+    )
     def get_asset_key(self, data: Union[SigmaDataset, SigmaWorkbook]) -> AssetKey:
         """Get the AssetKey for a Sigma object, such as a workbook or dataset."""
         return self.get_asset_spec(data).key