[FLINK-38839][runtime] Use constructor chaining in TransformDef

Use this(...) constructor chaining instead of duplicating field assignments
for better code maintainability.

Author: tchivs

flink-cdc-composer/src/main/java/org/apache/flink/cdc/composer/definition/TransformDef.java

@@ -72,7 +72,25 @@ public TransformDef(
         this.description = description;
         this.postTransformConverter = postTransformConverter;
     }
-
+    public TransformDef(
+            String sourceTable,
+            String projection,
+            String filter,
+            String primaryKeys,
+            String partitionKeys,
+            String tableOptions,
+            String description,
+            String postTransformConverter){
+        this.sourceTable = sourceTable;
+        this.projection = projection;
+        this.filter = filter;
+        this.primaryKeys = primaryKeys;
+        this.partitionKeys = partitionKeys;
+        this.tableOptions = tableOptions;
+        this.tableOptionsDelimiter = ",";
+        this.description = description;
+        this.postTransformConverter = postTransformConverter;
+    }
     public String getSourceTable() {
         return sourceTable;
     }