MOBILE-3807 usermenu: Hide usermenu button when the path is not main

src/core/features/mainmenu/components/user-menu-button/user-menu-button.html

@@ -1,9 +1,3 @@
-<core-user-avatar
-    *ngIf="siteInfo"
-    [user]="siteInfo"
-    class="core-bar-button-image clickable"
-    [linkProfile]="false"
-    (ariaButtonClick)="openUserMenu($event)"
-    role="button"
-    tabindex="0"
-></core-user-avatar>
+<core-user-avatar *ngIf="isMainScreen && siteInfo" [user]="siteInfo" class="core-bar-button-image clickable" [linkProfile]="false"
+    (ariaButtonClick)="openUserMenu($event)" role="button" tabindex="0" [attr.aria-label]="'core.user.account' | translate">
+</core-user-avatar>

src/core/features/mainmenu/components/user-menu-button/user-menu-button.ts

@@ -12,8 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import { Component } from '@angular/core';
+import { Component, OnInit } from '@angular/core';
 import { CoreSiteInfo } from '@classes/site';
+import { IonRouterOutlet } from '@ionic/angular';
 import { CoreSites } from '@services/sites';
 import { CoreDomUtils } from '@services/utils/dom';
 import { CoreMainMenuUserMenuComponent } from '../user-menu/user-menu';
@@ -27,17 +28,24 @@ import { CoreMainMenuUserMenuComponent } from '../user-menu/user-menu';
     selector: 'core-user-menu-button',
     templateUrl: 'user-menu-button.html',
 })
-export class CoreMainMenuUserButtonComponent {
+export class CoreMainMenuUserButtonComponent implements OnInit {
 
     siteInfo?: CoreSiteInfo;
+    isMainScreen = false;
 
-    constructor() {
+    constructor(protected routerOutlet: IonRouterOutlet) {
         const currentSite = CoreSites.getRequiredCurrentSite();
 
-        // @TODO: Check if the page where I currently am is at level 0.
         this.siteInfo = currentSite.getInfo();
     }
 
+    /**
+     * @inheritdoc
+     */
+    ngOnInit(): void {
+        this.isMainScreen = !this.routerOutlet.canGoBack();
+    }
+
     /**
      * Open User menu
      *