XWIKI-22365: Possible nullpointerexception when getting the extension index status

(cherry picked from commit 2fe73a62)

xwiki-platform-core/xwiki-platform-extension/xwiki-platform-extension-index/src/main/java/org/xwiki/extension/index/internal/job/ExtensionIndexJobScheduler.java

@@ -165,7 +165,7 @@ public ExtensionIndexStatus getStatus(Namespace namespace)
         ExtensionIndexStatus scheduledStatus = !id.equals(this.scheduledRequest.getId())
             ? (ExtensionIndexStatus) this.jobStore.getJobStatus(this.scheduledRequest.getId()) : null;
 
-        if (namespaceStatus != null
+        if (hasAStartDate(namespaceStatus)
             && (scheduledStatus == null || namespaceStatus.getStartDate().after(scheduledStatus.getStartDate())
                 || !((ExtensionIndexRequest) scheduledStatus.getRequest()).getNamespaces().contains(namespace))) {
             return namespaceStatus;
@@ -174,6 +174,11 @@ public ExtensionIndexStatus getStatus(Namespace namespace)
         return scheduledStatus;
     }
 
+    private boolean hasAStartDate(ExtensionIndexStatus status)
+    {
+        return status != null && status.getStartDate() != null;
+    }
+
     /**
      * @param namespace the new namespace to analyze
      */