test: update ArrayInsertUnsupportedArgs fallback reason wording

The CometScalaUDF fallback message was generalized from
'ScalaUDF has no native path' to 'expression has no native path' when
the dispatcher helper was extracted for reuse by CometDateFormat.

Author: andygrove

spark/src/test/scala/org/apache/comet/CometArrayExpressionSuite.scala

@@ -247,7 +247,7 @@ class CometArrayExpressionSuite extends CometTestBase with AdaptiveSparkPlanHelp
           .withColumn("arrUnsupportedArgs", expr("array_insert(arr, idx, 1)"))
         checkSparkAnswerAndFallbackReasons(
           df.select("arrUnsupportedArgs"),
-          Set("ScalaUDF has no native path", "unsupported arguments for ArrayInsert"))
+          Set("expression has no native path", "unsupported arguments for ArrayInsert"))
       }
     }
   }