refactor: clean up try_cache defaults and add SWR to sponsorship loaders

- Remove vestigial try_cache param from generate_qr_code (never used in body)
- Remove vestigial try_cache from ae_core_functions: load_ae_obj_id__site_domain,
  update_ae_obj_id_crud, update_ae_obj_id_crud_v2 (none referenced it in body)
- Add proper SWR pattern to load_ae_obj_id__sponsorship_cfg and
  load_ae_obj_id__sponsorship; change defaults from false to true
- Change load_ae_obj_id__event_file default try_cache from false to true
  (consistent with load_ae_obj_li__event_file)
- Change load_ae_obj_id__hosted_file default try_cache from false to true
  (consistent with load_ae_obj_li__hosted_file)
- Remove stale try_cache arg from element_ae_crud.svelte caller

src/lib/elements/element_ae_crud.svelte

@@ -125,7 +125,6 @@
                 field_name: field_name,
                 new_field_value: new_field_value,
                 params: {},
-                try_cache: true, // Defaulting to true as per project preference
                 log_lvl: 0
             })
             .then(function (results: any) {