Add back button.

libs/auth/src/angular/login/login.component.html

@@ -130,6 +130,19 @@
           {{ "loginWithDevice" | i18n }}
         </button>
       </ng-container>
+
+      <!-- Back button -->
+      <ng-container *ngIf="showBackButton()">
+        <button
+          type="button"
+          bitButton
+          block
+          buttonType="secondary"
+          (click)="toggleValidateEmail(false)"
+        >
+          {{ "back" | i18n }}
+        </button>
+      </ng-container>
     </div>
   </ng-container>
 </form>

libs/auth/src/angular/login/login.component.ts

@@ -557,4 +557,12 @@ export class LoginComponent implements OnInit, OnDestroy {
 
     this.messagingService.send("getWindowIsFocused");
   }
+
+  /**
+   * Helper function to determine if the back button should be shown.
+   * @returns true if the back button should be shown.
+   */
+  protected showBackButton(): boolean {
+    return this.validatedEmail && this.clientType !== ClientType.Browser;
+  }
 }