Fix: avoid crash in search options hook when class unloaded

[Rom1-B]

Checklist before requesting a review

Please delete options that are not relevant.

• 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 #N/A
• The search options hook crashed with a ClassNotFoundError when it ran before the plugin's main class was autoloaded, for example during the maintenance stage of a GLPI database migration.
• The hook now checks that the class is loaded before calling its static methods, so the migration can complete instead of aborting.

Screenshots (if appropriate):

[stonebuzz]

@Rom1-B

is needed for GLPI 10 version ?