[QA] Fix nightly failures

[nirajacharya2]

New version of php is causing phan errors

• activity , build: https://drone.owncloud.com/owncloud/activity/3997 test(refactor): fix nullable parameters error in nightly failure activity#1218
• files_antivirus , build: https://drone.owncloud.com/owncloud/files_antivirus/3631/2/3 test(refactor): fix nullable parameters error in nightly failure files_antivirus#557
• guests , build: https://drone.owncloud.com/owncloud/guests/3698 test(refactor): fix nullable parameters error in nightly failure guests#633
• password_policy , build: https://drone.owncloud.com/owncloud/password_policy/3277/3/3 @nirajacharya2 [test-only][full-ci] fixing phan error password_policy#408
• files_classifier , build: https://drone.owncloud.com/owncloud/files_classifier/4633 @nirajacharya2 https://github.com/owncloud/files_classifier/pull/1000

lib/DocumentProperties.php:60 PhanDeprecatedImplicitNullableParam Implicit nullable parameters (string $fileName = null) have been deprecated in PHP 8.4

• firewall , build: https://drone.owncloud.com/owncloud/firewall/3489 @nirajacharya2 https://github.com/owncloud/firewall/pull/761

lib/context.php:203 PhanDeprecatedImplicitNullableParam Implicit nullable parameters (\Sabre\DAV\Server $sabreServer = null) have been deprecated in PHP 8.4
rules/filesize.php:51 PhanDeprecatedImplicitNullableParam Implicit nullable parameters (\Sabre\DAV\Server $sabreServer = null) have been deprecated in PHP 8.4

• windows_network_drive, build: https://drone.owncloud.com/owncloud/windows_network_drive/3517 @nirajacharya2 https://github.com/owncloud/windows_network_drive/pull/482
• files_lifecycle, build: https://drone.owncloud.com/owncloud/files_lifecycle/3482 @nirajacharya2 https://github.com/owncloud/files_lifecycle/pull/585
• workflow, build: https://drone.owncloud.com/owncloud/workflow/2880 @nirajacharya2 https://github.com/owncloud/workflow/pull/313

[phil-davis]

phan is now checking for things that are deprecated in PHP 8.4.
It doesn't actually effect oC10, because that only supports PHP 7.4 at the moment.
But we may as well fix these, because it is easy to put a ? before each nullable parameter.

[PrajwolAmatya]

All related PRs have been merged and no issues is seen in CI. So, closing this issue.