Remove global service declarations and change to declarations upon usage. (#761)

* Remove global service declarations and change to declarations upon usage.

* Only load cava service if cava is enabled.

src/components/menus/dashboard/controls/helpers.ts

@@ -1,5 +1,7 @@
 import { bind, Variable } from 'astal';
-import { networkService } from 'src/lib/constants/services';
+import AstalNetwork from 'gi://AstalNetwork?version=0.1';
+
+const networkService = AstalNetwork.get_default();
 
 export const isWifiEnabled: Variable<boolean> = Variable(false);
 let wifiEnabledBinding: Variable<void> | undefined;