fix(migration): resolve compile error during plugin update with genericobject asset

[MyvTsv]

• I have performed a self-review of my code.
• I have added tests (when available) that prove my fix is effective or that my feature works.
• I have updated the CHANGELOG with a short functional description of the fix or new feature.
• This change requires a documentation update.

Description

• It fixes !41370
• When migrating the Fields plugin, container files are regenerated. However, if the targeted itemtype classes are not loaded, the file is not updated, which poses a problem in the event of a major change.

In GLPI 10, this behavior occurs when a container targets a deleted GenericObject: the CustomAsset is then not migrated to version 11 and the file remains obsolete.

[2026-01-20 13:57:37] glpi.ALERT: *** Fatal Compile Error: Declaration of PluginFieldsPlugingenericobjectprojecteurprojecteurtab::addField($fieldname, $type, array $options) must be compatible with PluginFieldsAbstractContainerInstance::addField($fieldname, $type, array $options = []) Backtrace : ...ericobjectprojecteurprojecteurtab.class.php:169

[stonebuzz]

I agree with this change and suggest waiting for more cases before validating the fix.

[Rom1-B]

OK, I'm not approving it just to block the merge and wait for other cases.