Fix(build): clean front files

[stonebuzz]

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

Fix #1018

Clean useless front files (dropdown)
Clean useless tpl file for dropdown (front)
Fix tpl (use of object::class instead 'itemtype' and add missing use statement)

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