Fix/6855 replace deprecated iconfig methods

[lfals]

Pull Request Description

This PR replaces deprecated \OCP\IConfig usage.

Files changed

• lib/Service/AccountService.php
• lib/Migration/Version12000Date20250517134200.php
• lib/Controller/AccountController.php
• tests/php/Unit/Service/AccountServiceTest.php

  Tests results:

composer test:unit -- --filter AccountService -> OK (25 tests, 50 assertions)

composer test:unit -- --filter AccountController -> OK (3 tests, 4 assertions)

Related Issue

Issue Number: #6855

Pull Request Type

• Refactoring (no functional changes, no api changes)

[welcome]

Thanks for opening your first pull request in this repository! ✌️

[vitormattos]

Look the CI, wasn't happy:

https://github.com/LibreSign/libresign/actions/runs/22426348763/job/65017841175?pr=6999

[lfals]

Fixed, ran the composer run cs:fix command as requested from the ci

[vitormattos]

/backport to stable33

[vitormattos]

Good work!

[backportbot-libresign]

The backport to stable33 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable33
git pull origin stable33

# Create the new backport branch
git checkout -b backport/6999/stable33

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick 54f8693c 4aebb374 485ca2b9 10b8b454 a2a5e046

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/6999/stable33

Error: Failed to push branch backport/6999/stable33: fatal: could not read Username for 'https://github.com': No such device or address

---

Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.

[vitormattos]

/backport to stable33

[vitormattos]

/backport to stable32