refactor(docs-infra): remove unused custom element (#27250)

PR Close #27250

aio/scripts/_payload-limits.json

@@ -2,8 +2,8 @@
   "aio": {
     "master": {
       "uncompressed": {
-        "runtime": 3799,
+        "runtime": 3713,
-        "main": 501972,
+        "main": 500343,
         "polyfills": 53926
       }
     }

aio/src/app/custom-elements/element-registry.ts

@@ -36,10 +36,6 @@ export const ELEMENT_MODULE_PATHS_AS_ROUTES = [
     selector: 'code-tabs',
     loadChildren: './code/code-tabs.module#CodeTabsModule'
   },
-  {
-    selector: 'expandable-section',
-    loadChildren: './expandable-section/expandable-section.module#ExpandableSectionModule'
-  },
   {
     selector: 'live-example',
     loadChildren: './live-example/live-example.module#LiveExampleModule'

aio/src/app/custom-elements/expandable-section/expandable-section.component.html

@@ -1,7 +0,0 @@
-<mat-expansion-panel style="background: inherit">
-  <mat-expansion-panel-header>
-    {{title}}
-  </mat-expansion-panel-header>
-
-  <ng-content></ng-content>
-</mat-expansion-panel>

aio/src/app/custom-elements/expandable-section/expandable-section.component.ts

@@ -1,11 +0,0 @@
-/* tslint:disable component-selector */
-import {Component, Input} from '@angular/core';
-
-/** Custom element wrapper for the material expansion panel with a title input. */
-@Component({
-  selector: 'aio-expandable-section',
-  templateUrl: 'expandable-section.component.html',
-})
-export class ExpandableSectionComponent {
-  @Input() title;
-}

aio/src/app/custom-elements/expandable-section/expandable-section.module.ts

@@ -1,13 +0,0 @@
-import { NgModule, Type } from '@angular/core';
-import { ExpandableSectionComponent } from './expandable-section.component';
-import { WithCustomElementComponent } from '../element-registry';
-import { MatExpansionModule } from '@angular/material';
-
-@NgModule({
-  imports: [ MatExpansionModule ],
-  declarations: [ ExpandableSectionComponent, ],
-  entryComponents: [ ExpandableSectionComponent ]
-})
-export class ExpandableSectionModule implements WithCustomElementComponent {
-  customElementComponent: Type<any> = ExpandableSectionComponent;
-}