Fix: fields values update checks (GLPI 12)

[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

• Fields values are now only written through the item and its fields tab, so the expected checks always apply.

• forward-port: Fix: fields values update checks (GLPI 11) #1299

Screenshots (if appropriate):