fix(clickpipes): update sorting key handling and update example (#358)

Author: jkaflik

examples/clickpipe/kafka_confluent/main.tf

@@ -52,6 +52,8 @@ resource "clickhouse_clickpipe" "kafka_confluent" {
       engine = {
         type = "MergeTree"
       }
+
+      sorting_key = ["my_field1", "my_field2"]
     }
 
     columns = [
@@ -67,8 +69,12 @@ resource "clickhouse_clickpipe" "kafka_confluent" {
 
   field_mappings = [
     {
-      source_field      = "my_field"
+      source_field      = "my_field1"
       destination_field = "my_field1"
+    },
+    {
+      source_field      = "my_field2"
+      destination_field = "my_field2"
     }
   ]
 }

pkg/resource/clickpipe.go

@@ -733,7 +733,7 @@ func (c *ClickPipeResource) Create(ctx context.Context, request resource.CreateR
 		sortingKey := make([]string, len(tableDefinitionModel.SortingKey.Elements()))
 
 		for i, sortingKeyModel := range tableDefinitionModel.SortingKey.Elements() {
-			sortingKey[i] = sortingKeyModel.String()
+			sortingKey[i] = sortingKeyModel.(types.String).ValueString()
 		}
 
 		tableEngineModel := models.ClickPipeDestinationTableEngineModel{}