Fix view result (#3176)

This PR fixes an issue where operators marked for viewing results did
not display the expected results due to a mismatch caused by
string-based comparison instead of using operator identities. By
updating the matching logic to rely on operator identities, this change
ensures accurate identification of marked operators and correct display
of their results.

core/amber/src/main/scala/edu/uci/ics/texera/workflow/WorkflowCompiler.scala

@@ -28,7 +28,7 @@ class WorkflowCompiler(
       errorList: Option[ArrayBuffer[(OperatorIdentity, Throwable)]]
   ): PhysicalPlan = {
     val terminalLogicalOps = logicalPlan.getTerminalOperatorIds
-    val toAddSink = (terminalLogicalOps ++ logicalOpsToViewResult).toSet
+    val toAddSink = (terminalLogicalOps ++ logicalOpsToViewResult.map(OperatorIdentity(_))).toSet
     var physicalPlan = PhysicalPlan(operators = Set.empty, links = Set.empty)
     // create a JSON object that holds pointers to the workflow's results in Mongo
     val resultsJSON = objectMapper.createObjectNode()