[Feature][transform-v2] sql transform support multi_if function

Author: CosmosNi

Diff for: seatunnel-e2e/seatunnel-transforms-v2-e2e/seatunnel-transforms-v2-e2e-part-2/src/test/resources/sql_transform/func_multi_if.conf

@@ -52,7 +52,8 @@ transform {
         score,
         name,
         MULTI_IF(age < 18, 'Minor', age < 30, 'Young Adult', age < 40, 'Adult', 'Senior') as age_category,
-        MULTI_IF(score >= 90, 'A', score >= 80, 'B', score >= 70, 'C', score >= 60, 'D', 'F') as grade
+        MULTI_IF(score >= 90, 'A', score >= 80, 'B', score >= 70, 'C', score >= 60, 'D', 'F') as grade,
+        MULTI_IF(score >= 90, 'excellent', 'pass') as grade_category,
       FROM fake
     """
   }
@@ -93,6 +94,13 @@ sink {
           field_value = [
             {equals_to = "B"}
           ]
+        },
+        {
+          field_name = "grade_category"
+          field_type = "string"
+          field_value = [
+            {equals_to = "pass"}
+          ]
         }
       ]
     }