fix(provider/big_query_source): manage sync engine type during creation

Author: cysp

internal/provider/big_query_source_model_request.go

@@ -15,6 +15,11 @@ func (m *BigQuerySourceModel) ToCreateSourceData(_ context.Context) (cm.CreateSo
 		},
 	}
 
+	syncEngine := m.SyncEngine.ValueString()
+	if syncEngine != "" {
+		body.Connection.SyncEngine.SetTo(syncEngine)
+	}
+
 	label := m.Label.ValueString()
 	if label != "" {
 		body.Connection.Label.SetTo(label)