Fix - Visibility conditions not working on tree cascade dropdown questions

[RomainLvr]

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 !44659
• Here is a brief description of what this PR does

ItemAsTextConditionHandler uses getName() which returns only the item's own name. For tree dropdowns, a child item's name does not include its ancestors, so a condition like "contains Parent" always failed. Fixed by introducing TreeCascadeItemAsTextConditionHandler in the plugin, which uses completename ("Parent > Child") for CommonTreeDropdown items. TreeCascadeDropdownQuestion::getConditionHandlers() is overridden to substitute this handler.