MOBILE-4616 chat: Move chat constants to a file

src/addons/mod/chat/chat-lazy.module.ts

@@ -80,4 +80,4 @@ const routes: Routes = [
         AddonModChatSessionMessagesPage,
     ],
 })
-export class AddonModChatLazyModule {}
+export default class AddonModChatLazyModule {}

src/addons/mod/chat/chat.module.ts

@@ -28,7 +28,7 @@ import { ADDON_MOD_CHAT_COMPONENT, ADDON_MOD_CHAT_PAGE_NAME } from './constants'
 const routes: Routes = [
     {
         path: ADDON_MOD_CHAT_PAGE_NAME,
-        loadChildren: () => import('./chat-lazy.module').then(m => m.AddonModChatLazyModule),
+        loadChildren: () => import('./chat-lazy.module'),
     },
 ];