core: remove deprecation

packages/onlyoffice/index.ts

@@ -1,8 +1,22 @@
-import { SystemModel, UiContextBase } from 'hydrooj';
+import { Context, SystemModel, UiContextBase } from 'hydrooj';
 
 declare module 'hydrooj' {
     interface UiContextBase {
         onlyofficeApi?: string;
     }
 }
-UiContextBase.onlyofficeApi = SystemModel.get('onlyoffice.api');
+
+export function apply(ctx: Context) {
+    Object.defineProperty(UiContextBase, 'onlyofficeApi', {
+        configurable: true,
+        enumerable: true,
+        get() {
+            return SystemModel.get('onlyoffice.api');
+        },
+    });
+    ctx.on('dispose', () => {
+        Object.defineProperty(UiContextBase, 'onlyofficeApi', {
+            enumerable: false,
+        });
+    });
+}