mark as deprecated instead

Author: SCHJonathan

sql/connect/common/src/main/protobuf/spark/connect/pipelines.proto

@@ -121,8 +121,11 @@ message PipelineCommand {
     // Name of the dataset this flow writes to. Can be partially or fully qualified.
     optional string target_dataset_name = 3;
 
+    // [Deprecated] An unresolved relation that defines the dataset's flow.
+    optional spark.connect.Relation relation = 4 [deprecated = true];
+
     // The result of executing the flow's query function
-    optional QueryFunctionResult result = 4;
+    optional QueryFunctionResult result = 7;
 
     // SQL configurations set when running this flow.
     map<string, string> sql_conf = 5;