Render tooltip in needle table to reveal absolute time

Tooltips are used in other places to show the time to
disambiguate relative times.

Related: https://progress.opensuse.org/issues/167635

assets/javascripts/admin_needle.js

@@ -30,7 +30,7 @@ function setupAdminNeedles() {
           if (type === 'display' && data != 'never') {
             var ri = 'last_seen_link';
             if (data == row['last_match']) ri = 'last_match_link';
-            return "<a href='" + row[ri] + "'>" + jQuery.timeago(new Date(data)) + '</a>';
+            return "<a href='" + row[ri] + "' title='" + data + "Z'>" + jQuery.timeago(new Date(data)) + '</a>';
           } else {
             return data;
           }

t/ui/21-admin-needles.t

@@ -165,6 +165,11 @@ subtest 'dereference symlink when displaying needles info' => sub {
     is((shift @symlink_needle_tds)->get_text(), 'bootloader.json', 'symlink needle file name is displayed correctly');
     my $last_used_td = shift @symlink_needle_tds;
     is($last_used_td->get_text(), 'a day ago', 'symlink needle last use is displayed correctly');
+    is(
+        $last_used_td->child('a')->get_attribute('title'),
+        $real_needle->last_seen_time . 'Z',
+        'symlink needle last use tooltip is displayed correctly'
+    );
     like(
         $driver->find_child_element($last_used_td, 'a')->get_attribute('href'),
         qr/admin\/needles\/$last_seen_module_id\/$real_needle_id/,