[CL-696] un-revert "various drawer improvements" + bug fix (#14887)

* Revert "Revert "[CL-622][CL-562][CL-621][CL-632] various drawer improvements …"

This reverts commit 4b32d1f9dd.

* fix virtual scroll: add .cdk-virtual-scrollable to scroll viewport target

* remove references to main el

* use directives instead of querySelector (#14950)

* remove references to main el

* wip

* banish querySelector to the shadow realm

* revert apps/ files

* Add virtual scrolling docs

Co-authored-by: Vicki League <vleague@bitwarden.com>

* add jsdoc

* run eslint

* fix skip links bug

* Update libs/components/src/layout/layout.component.ts

Co-authored-by: Vicki League <vleague@bitwarden.com>

* update tab handler

* only run on tab

* fix lint

* fix virtual scroll issue due to Angular 19 upgrade (#15193)

thanks Vicki

---------

Co-authored-by: Vicki League <vleague@bitwarden.com>

libs/components/src/utils/has-scrolled-from.ts

@@ -0,0 +1,41 @@
+import { CdkScrollable } from "@angular/cdk/scrolling";
+import { Signal, inject, signal } from "@angular/core";
+import { toObservable, toSignal } from "@angular/core/rxjs-interop";
+import { map, startWith, switchMap } from "rxjs";
+
+export type ScrollState = {
+  /** `true` when the scrollbar is not at the top-most position */
+  top: boolean;
+
+  /** `true` when the scrollbar is not at the bottom-most position */
+  bottom: boolean;
+};
+
+/**
+ * Check if a `CdkScrollable` instance has been scrolled
+ * @param scrollable The instance to check, defaults to the one provided by the current injector
+ * @returns {Signal<ScrollState>}
+ */
+export const hasScrolledFrom = (scrollable?: Signal<CdkScrollable>): Signal<ScrollState> => {
+  const _scrollable = scrollable ?? signal(inject(CdkScrollable));
+  const scrollable$ = toObservable(_scrollable);
+
+  const scrollState$ = scrollable$.pipe(
+    switchMap((_scrollable) =>
+      _scrollable.elementScrolled().pipe(
+        startWith(null),
+        map(() => ({
+          top: _scrollable.measureScrollOffset("top") > 0,
+          bottom: _scrollable.measureScrollOffset("bottom") > 0,
+        })),
+      ),
+    ),
+  );
+
+  return toSignal(scrollState$, {
+    initialValue: {
+      top: false,
+      bottom: false,
+    },
+  });
+};