FIX Don't remove jobs when processing via publish job

WorkflowPublishTargetJob::process() triggers a onBeforeWrite() which in turn can lead to job descriptors being deleted while still being used.
Don't delete completed jobs when setting up new ones.

src/Extensions/WorkflowEmbargoExpiryExtension.php

@@ -182,7 +182,7 @@ public function updateCMSFields(FieldList $fields)
     public function clearPublishJob()
     {
         $job = $this->owner->PublishJob();
-        if ($job && $job->exists()) {
+        if ($job && $job->exists() && !$job->JobFinished) {
             $job->delete();
         }
         $this->owner->PublishJobID = 0;
@@ -195,7 +195,7 @@ public function clearUnPublishJob()
     {
         // Cancel any in-progress unpublish job
         $job = $this->owner->UnPublishJob();
-        if ($job && $job->exists()) {
+        if ($job && $job->exists() && !$job->JobFinished) {
             $job->delete();
         }
         $this->owner->UnPublishJobID = 0;
@@ -299,6 +299,10 @@ public function onBeforeWrite()
         if (!$this->owner->ID) {
             return;
         }
+
+        if ($this->owner->hasMethod('isPublishJobRunning') && $this->owner->isPublishJobRunning()) {
+            return;
+        }
 
         // Check requested dates of publish / unpublish, and whether the page should have already been unpublished
         $now = DBDatetime::now()->getTimestamp();