The buffer section would list `unlisted` buffer

**Describe the bug**
If there are some buffers are unlisted, the buffer section would still have those buffers listed as the `ignored = true` did not contain unlisted buffers in the `buffers.lua`

**To Reproduce**
1. Open any two files with `nvim`
2. Set one of them `:set nobuflisted`
3. `SidebarNvimToggle`

**Expected behavior**
No unlisted buffer