[Bug]: after activating argon2 derivation, i can no longer modify my passwords

Bug description

today i've upgraded to passy-1.7.0 on both my mobile (f-droid) and my laptop (flatpak). i've activated "Argon2" key derivation, and ran a synchronization between the two devices, which worked nicely.

after that, I've changed one of my password entries on the laptop (it previously only had a 2FA setup, and an empty password; i've now also added a proper password), which resulted in:

several seconds of a progress bar
then i'm asked for my password
several seconds of a progress bar again
then i'm asked for my password again
several seconds of a progress bar again
then i'm asked for my password again
repeat ad lib

at some point, passy would simply crash (see stderr below).

the "several seconds" where the progress bar is displayed, range from ~3 seconds to something that feels like a minute.

Expected outcome

i expected that the new password would be added to the entry.

Steps to reproduce

No response

Error log

$ flatpak run io.github.glitterware.Passy

(passy:2): Gdk-CRITICAL **: 18:43:00.126: gdk_window_get_state: assertion 'GDK_IS_WINDOW (window)' failed
flutter: FileSystemException: Cannot open file, path = '/home/<<<USER>>>/Documents/Passy/accounts/<<<USER>>>/favorites.enc' (OS Error: Too many open files, errno = 24)
flutter: #0      _File.throwIfError (dart:io/file_impl.dart:675)
flutter: #1      _File.openSync (dart:io/file_impl.dart:490)
flutter: #2      _File.readAsBytesSync (dart:io/file_impl.dart:574)
flutter: #3      _File.readAsStringSync (dart:io/file_impl.dart:624)
flutter: #4      EncryptedJsonFile.reloadSync (package:passy/passy_data/encrypted_json_file.dart:54)
flutter: #5      LoadedAccount.reloadFavoritesSync (package:passy/passy_data/loaded_account.dart:880)
flutter: #6      _PasswordScreen.build (package:passy/screens/password_screen.dart:155)
flutter: #7      StatefulElement.build (package:flutter/src/widgets/framework.dart:5409)
flutter: #8      ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:5297)
flutter: #9      StatefulElement.performRebuild (package:flutter/src/widgets/framework.dart:5462)
flutter: #10     Element.rebuild (package:flutter/src/widgets/framework.dart:5016)
flutter: #11     BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2779)
flutter: #12     WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:916)
flutter: #13     RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:360)
flutter: #14     SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1297)
flutter: #15     SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1227)
flutter: #16     SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:1085)
flutter: #17     _invoke (dart:ui/hooks.dart:170)
flutter: #18     PlatformDispatcher._drawFrame (dart:ui/platform_dispatcher.dart:401)
flutter: #19     _drawFrame (dart:ui/hooks.dart:140)

App version

v1.7.0 - Better Synchronization

Submission checklist

[X] I have specified the problem in the issue title
[X] I have provided a verbose description of the problem

GlitterWare / Passy