Enable astro/tsconfigs/strictest in the shared package (#2836)

shared/components/navbar/Sidebar.astro

@@ -5,14 +5,14 @@ import NavbarSide from './NavbarSide.astro'
 import NavbarMenu from './NavbarMenu.astro'
 
 interface Props {
-  dark?: boolean
+  dark?: boolean | undefined
   breakpoint?: string
   /** layout-sidebar-end — navbar-end class */
-  end?: boolean
+  end?: boolean | undefined
   /** layout-navbar-transparent — navbar-transparent class */
-  transparent?: boolean
+  transparent?: boolean | undefined
   /** equivalent of the page-menu front matter (active menu entry), e.g. "layout.vertical" */
-  pageMenu?: string
+  pageMenu?: string | undefined
 }
 
 const { dark = false, breakpoint = 'lg', end = false, transparent = false, pageMenu } = Astro.props