fix(container.class.php): fix the name of dropdown fields in log

[TarekRemo]

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.

Description

• It fixes !44835
• Before this fix, the name of dropdown fields was missing in logs.
• For dropdown fields (both custom and dropdown-<ItemType>), the search option sets:
  • field → completename or name (from the foreign table, e.g. glpi_users.name)
  • linkfield → the actual column in the container table (e.g. usersfield_0)
• So, the current code compares name against the actual DB column key when updating = it never matches -> the name of the field doesn't appear.
• fix: add $searchoption['linkfield'] == $key to check the the actual column in the container table.

[stonebuzz]

Awaiting customers feedback