Fix eratic test for POST /api/pleroma/admin/reports/:id/notes

It retrieved two ReportNotes and then checked one of them. But the order isn't guaranteed, while the test tested on the content of the first ReportNote.

I made the test on the content more generic

test/pleroma/web/admin_api/controllers/report_controller_test.exs

@@ -369,7 +369,8 @@ defmodule Pleroma.Web.AdminAPI.ReportControllerTest do
       refute is_nil(note)
 
       assert note["user"]["nickname"] == admin.nickname
-      assert note["content"] == "this is disgusting!"
+      # We use '=~' because the order of the notes isn't guaranteed
+      assert note["content"] =~ "this is disgusting"
       assert note["created_at"]
       assert response["total"] == 1
     end