Add another Cockpit log entry detail needle

Stupid Firefox survey means the thing we usually check isn't
always on the screen. This one checks for PRIORITY.

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

needles/cockpit/logs_entry_detail-priority-20210422.json

@@ -0,0 +1,15 @@
+{
+  "area": [
+    {
+      "ypos": 653,
+      "width": 78,
+      "height": 14,
+      "type": "match",
+      "xpos": 458
+    }
+  ],
+  "properties": [],
+  "tags": [
+    "cockpit_logs_detail"
+  ]
+}