fix: fix observable

src/http/index.ts

@@ -1,4 +1,9 @@
-import type { HttpFeature } from '@ngify/http';
+import type { HttpFeature, HttpInterceptor } from '@ngify/http';
+import { InjectionToken } from 'injection-js';
+
+export const HTTP_INTERCEPTORS = new InjectionToken<readonly HttpInterceptor[]>(
+  'HTTP_INTERCEPTORS'
+);
 
 export function provideHttpClient() {
   // todo