[tools][CouchDB_MRI_Importer] Fix date in MRI data (#8851)

- Fix date imported into DQT to be a real date rather than a unix timestamp.
- Fix incorrect order of parameters to `join` in import script

tools/CouchDB_MRI_Importer.php

@@ -249,7 +249,10 @@ function _addMRIHeaderInfo($FileObj, $scan_type)
             $FileObj,
             'acquisition_date'
         );
-        $header['FileInsertDate_'.$type]      = $FileObj->getParameter('InsertTime');
+        $header['FileInsertDate_'.$type]      = date(
+            'Y-m-d',
+            $FileObj->getParameter('InsertTime')
+        );
         $header['SeriesDescription_'.$type]   = $FileObj->getParameter($ser_desc);
         $header['SeriesNumber_'.$type]        = $FileObj->getParameter($ser_num);
         $header['EchoTime_'.$type]            = number_format(
@@ -438,7 +441,7 @@ function updateCandidateDocs($data, $ScanTypes)
                 $row['PSCID'],
                 $row['Visit_label'],
             ];
-            $docid      = 'MRI_Files:' . join($identifier, '_');
+            $docid      = 'MRI_Files:' . join('_', $identifier);
             unset($doc['PSCID']);
             unset($doc['Visit_label']);
             unset($doc['SessionID']);