refactor(external-playback): improve session handling and remove dismiss functionality

libs/workspace/shell/feature/src/lib/workspace-shell/workspace-shell.component.html

@@ -261,7 +261,6 @@
                 <app-external-playback-dock
                     [session]="session"
                     (closeClicked)="closeActiveExternalSession()"
-                    (dismissClicked)="dismissActiveExternalSession()"
                 />
             </footer>
         }

libs/workspace/shell/feature/src/lib/workspace-shell/workspace-shell.component.ts

@@ -312,10 +312,6 @@ export class WorkspaceShellComponent {
             this.externalPlayback.activeSession()
         );
     }
-
-    dismissActiveExternalSession(): void {
-        this.externalPlayback.dismissActiveSession();
-    }
     readonly searchPlaceholder = computed(() => {
         this.languageTick();