fix: unify encryption across platforms

[MrCyjaneK]

Issue Number (if Applicable): Fixes #

Description

Please include a summary of the changes and which issue is fixed / feature is added.

Pull Request - Checklist

• Initial Manual Tests Passed
• Double check modified code and verify it with the feature/task requirements
• Format code
• Look for code duplication
• Clear naming for variables and methods
• Manual tests in accessibility mode (TalkBack on Android) passed

[OmarHatem28]

also can we add some tests to this migration, add cases for correct migration and for failed migration, and for writing multiple times together, and reading multiple times together, etc...

[OmarHatem28]

I think we should wrap this in a try/catch, so a failure here won't stop wallet from opening/read from completing

[MrCyjaneK]

it shouldn't fail at all and if it does it better do so loudly

[OmarHatem28]

it will not fail loudly, it will just fail to open the wallet silently, and the user will end up with a wallet that can't be opened, and since it passed our tests, so we don't need it to fail loudly, we need it to work, and for any reason the user might have, we shouldn't block him from opening his wallet, we can add another way to check if the migration worked tho, but it will be a bit of a headache

[MrCyjaneK]

True, but it can only fail if

1. secure random is unavailable (impossible)
2. file wasn't written (out of space / wrong permissions)

and even if it fails a fix is a matter of reopening the app after solving the problem. Unless I'm missing something

[github-actions]

changes in dependencies

changed git refs:
  cake_backup
    url   https://github.com/cake-tech/cake_backup.git -> https://github.com/cake-tech/cake_backup.git
    ref   3aba867dcab6737f6707782f5db15d71f303db38 -> b5d86a2a21e1c186cd0baa4df1f3a4f3f9413056
    path  - -> -
     lib/backup.dart       | 90 ++++++++++++++++++++++++++++++++++++++-------------
     test/backup_test.dart | 50 +++++++++++++++++++++++++---
     2 files changed, 114 insertions(+), 26 deletions(-)