I found the problem. Comparing the files in the backup copy of the app to the files in the app after running through the Packaging Tool process, and systematically undoing any changes between the two versions, I found that the culprit was the local.meta file in the $SPLUNK_HOME\etc\apps\app\metadata folder. One of the recommendations made by the Packaging Tool was to merge the contents of the local.meta file with the default.meta file, then delete the local.meta file from the app. After restoring the local.meta file to the app, the delete menu item for the dashboards and reports for the app was restored in the Splunk Enterprise Web UI. I suggest that anyone who runs into this issue when preparing an app for deployment to Splunk Cloud, restore this file after running through the Packaging Tool process, so that development of the app can continue on your Splunk Enterprise System.
... View more