Add a cockpit logs_entry_detail variant needle

For a while, it seems like the test was often hitting a message
where the field we match on isn't actually visible because a lot
of other fields are shown first. So, add a variant needle that
matches on a different field, the message ID.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

needles/cockpit/logs_entry_detail-messageid-20230517.json

@@ -0,0 +1,15 @@
+{
+  "area": [
+    {
+      "height": 16,
+      "width": 91,
+      "ypos": 721,
+      "xpos": 263,
+      "type": "match"
+    }
+  ],
+  "properties": [],
+  "tags": [
+    "cockpit_logs_detail"
+  ]
+}