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/bar/utils/monitors.ts

@@ -1,7 +1,9 @@
-import { hyprlandService } from 'src/lib/constants/services';
 import { Gdk } from 'astal/gtk3';
+import AstalHyprland from 'gi://AstalHyprland?version=0.1';
 import { BarLayout, BarLayouts } from 'src/lib/types/options';
 
+const hyprlandService = AstalHyprland.get_default();
+
 type GdkMonitors = {
     [key: string]: {
         key: string;