Narrow component prop types, remove unused props and dead code (#2838)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

shared/components/navbar/Sidebar.astro

@@ -3,10 +3,11 @@ import NavbarToggler from './NavbarToggler.astro'
 import Logo from './Logo.astro'
 import NavbarSide from './NavbarSide.astro'
 import NavbarMenu from './NavbarMenu.astro'
+import type { Breakpoint } from './NavbarSide.astro'
 
 interface Props {
   dark?: boolean | undefined
-  breakpoint?: string
+  breakpoint?: Breakpoint | undefined
   /** layout-sidebar-end — navbar-end class */
   end?: boolean | undefined
   /** layout-navbar-transparent — navbar-transparent class */