[hotfix][runtime-web] Handle hyphen in the rescales/configuration tab when the schedulerExecutionMode variable value is null

Co-authored-by: Matthias Pohl <mpohl@confluent.io>
Co-authored-by: Yuepeng Pan <hipanyuepeng@gmail.com>

Author: 3 people

flink-runtime-web/web-dashboard/src/app/pages/job/rescales/job-rescales.component.html

@@ -391,8 +391,7 @@ <h3><strong>Rescale Details</strong></h3>
         <ng-container *ngIf="rescalesConfig">
           <tr>
             <td>Scheduler Execution Mode</td>
-            <td *ngIf="rescalesConfig['schedulerExecutionMode'] === 'REACTIVE'">REACTIVE</td>
-            <td *ngIf="rescalesConfig['schedulerExecutionMode'] !== 'REACTIVE'"></td>
+            <td>{{ rescalesConfig['schedulerExecutionMode'] || '-' }}</td>
           </tr>
           <tr>
             <td>Submission Resource Wait Timeout</td>