opt pull ab (#7508)

1. Test legacy/new mode only upon logging out.
2. Avoid pulling all data unnecessarily:
* On startup: Retrieve list, current, and personal data.
* On refresh: Retrieve list and current data.
* On changing AB/switching tabs: Attempt to pull current data if not initialized.
3. Cache only personal and current AB.
4. Synchronize current AB from recent.
5. Remove AB loading CircularProgressIndicator.

Signed-off-by: 21pages <pages21@163.com>

flutter/lib/common/widgets/address_book.dart

@@ -46,12 +46,6 @@ class _AddressBookState extends State<AddressBook> {
               child: ElevatedButton(
                   onPressed: loginDialog, child: Text(translate("Login"))));
         } else {
-          if (gFFI.abModel.currentAbLoading.value &&
-              gFFI.abModel.currentAbEmtpy) {
-            return const Center(
-              child: CircularProgressIndicator(),
-            );
-          }
           return Column(
             children: [
               buildErrorBanner(context,