Fixes the breadcrumb container when in issue boards

Closes #36561

app/views/layouts/nav/_breadcrumbs.html.haml

 - breadcrumb_link = breadcrumb_title_link
+- container = @no_breadcrumb_container ? 'container-fluid' : container_class
 - hide_top_links = @hide_top_links || false
 %nav.breadcrumbs{ role: "navigation" }
-  .breadcrumbs-container{ class: [container_class, @content_class] }
+  .breadcrumbs-container{ class: [container, @content_class] }
     - if defined?(@new_sidebar)
       = button_tag class: 'toggle-mobile-nav', type: 'button' do
         %span.sr-only Open sidebar

app/views/projects/boards/_show.html.haml

+- @no_breadcrumb_container = true
 - @no_container = true
 - @content_class = "issue-boards-content"
 - page_title "Boards"

changelogs/unreleased/issue-boards-breadcrumbs-container.yml

+---
+title: Fix breadcrumbs container in issue boards
+merge_request:
+author:
+type: fixed