fix: theme switcher (#24209)

Author: jrasm91

web/src/lib/managers/theme-manager.svelte.ts

@@ -2,6 +2,7 @@ import { browser } from '$app/environment';
 import { Theme } from '$lib/constants';
 import { eventManager } from '$lib/managers/event-manager.svelte';
 import { PersistedLocalStorage } from '$lib/utils/persisted';
+import { theme as uiTheme, type Theme as UiTheme } from '@immich/ui';
 
 export interface ThemeSetting {
   value: Theme;
@@ -71,6 +72,8 @@ class ThemeManager {
 
     this.#theme.current = theme;
 
+    uiTheme.value = theme.value as unknown as UiTheme;
+
     eventManager.emit('ThemeChange', theme);
   }
 }