fix: include gRPC status code in WeaviateDeleteManyError messages (Fixes #1030)

Previously, batch delete failures produced unhelpful error messages like
'Query call with protocol GRPC delete failed with message unavailable.'
without indicating the gRPC status code.

Now the error includes the status code name (e.g., [UNAVAILABLE],
[DEADLINE_EXCEEDED]) to help users diagnose whether the failure is due
to server overload, timeout, or other gRPC-level issues.

Affects both sync (ConnectionSync.grpc_batch_delete) and async
(ConnectionAsync.grpc_batch_delete) code paths.

Signed-off-by: rtmalikian <rtmalikian@gmail.com>

Author: rtmalikian

weaviate/connect/v4.py

@@ -1052,7 +1052,7 @@ def grpc_batch_delete(
             error = cast(Call, e)
             if error.code() == StatusCode.PERMISSION_DENIED:
                 raise InsufficientPermissionsError(error)
-            raise WeaviateDeleteManyError(str(error.details()))
+            raise WeaviateDeleteManyError(f"[{error.code().name}] {error.details()}")
 
     def grpc_tenants_get(
         self, request: tenants_pb2.TenantsGetRequest
@@ -1232,7 +1232,7 @@ async def grpc_batch_delete(
         except AioRpcError as e:
             if e.code().name == PERMISSION_DENIED:
                 raise InsufficientPermissionsError(e)
-            raise WeaviateDeleteManyError(str(e))
+            raise WeaviateDeleteManyError(f"[{e.code().name}] {e.details()}")
 
     async def grpc_batch_stream(
         self,