fix: update arrow logic collapsible sidebar

{{ if .Site.Params.options.collapsibleSidebar -}}

  <ul class="list-unstyled collapsible-sidebar">

  {{ $currentPage := . -}}

  {{ range $index, $value := .Site.Menus.docs -}}

  {{ range $index, $element := .Site.Menus.docs -}}

  {{- $active := or ($currentPage.IsMenuCurrent "docs" .) ($currentPage.HasMenuCurrent "docs" .) -}}

  {{- $active = or $active (eq $currentPage.Section .Identifier) -}}

    <li class="mb-1">

      <button class="btn btn-toggle align-items-center rounded collapsed" data-bs-toggle="collapse" data-bs-target="#{{ .Identifier }}" aria-expanded="{{ if not $index }}true{{ else }}false{{ end }}">

      <button class="btn btn-toggle align-items-center rounded collapsed" data-bs-toggle="collapse" data-bs-target="#{{ .Identifier }}" aria-expanded="{{ if $active }}true{{ else }}false{{ end }}">

        {{ .Name }}

      </button>

      {{ if .HasChildren -}}

      {{- $active := or ($currentPage.IsMenuCurrent "docs" .) ($currentPage.HasMenuCurrent "docs" .) -}}

      {{- $active = or $active (eq $currentPage.Section .Identifier) -}}

      <div class="collapse{{ if $active }} show{{ end }}" id="{{ .Identifier }}">

        <ul class="btn-toggle-nav list-unstyled fw-normal pb-1 small">

        {{ range .Children -}}