fix(home): reset main-content scroll on route navigation so pages open at the top

PROD-8423: .tb-main-content (the scroll container holding the router-outlet in home.component.html) keeps its scrollTop across route changes, so navigating from a scrolled-down IoT Hub home to a child page (e.g. Calculated Fields) opened the new page already scrolled. Angular's scrollPositionRestoration only handles window scroll, not arbitrary containers. Add a #mainContent ref, capture the ElementRef, and reset its scroll position in the existing (activate) handler so every route navigation lands at the top.

ui-ngx/src/app/modules/home/home.component.html

@@ -79,7 +79,7 @@
       <mat-progress-bar color="warn" style="z-index: 10; margin-bottom: -4px; width: 100%;" mode="indeterminate"
                         *ngIf="!hideLoadingBar && (isLoading$ | async)">
       </mat-progress-bar>
-      <div tb-toast class="tb-main-content flex flex-1 flex-col">
+      <div #mainContent tb-toast class="tb-main-content flex flex-1 flex-col">
         <router-outlet (activate)="activeComponentChanged($event)"></router-outlet>
       </div>
     </div>

ui-ngx/src/app/modules/home/home.component.ts

@@ -58,6 +58,8 @@ export class HomeComponent extends PageComponent implements AfterViewInit, OnIni
   @ViewChild('sidenav')
   sidenav: MatSidenav;
 
+  @ViewChild('mainContent', { static: true }) mainContent: ElementRef<HTMLElement>;
+
   @ViewChild('searchInput') searchInputField: ElementRef;
 
   fullscreenEnabled = screenfull.isEnabled;
@@ -136,6 +138,7 @@ export class HomeComponent extends PageComponent implements AfterViewInit, OnIni
 
   activeComponentChanged(activeComponent: any) {
     this.activeComponentService.setCurrentActiveComponent(activeComponent);
+    this.mainContent?.nativeElement?.scrollTo({ top: 0, left: 0 });
     if (!this.activeComponent) {
       setTimeout(() => {
         this.updateActiveComponent(activeComponent);