Fix massive action add multiple dropdown

[Lainow]

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 !38850
• Here is a brief description of what this PR does
  Correction of the bulk action to add value to multiple drop-down fields, specifically the ‘Add’ option, which now compares the values in the table rather than the keys in order to prevent duplicates.

Screenshots (if appropriate):

[stonebuzz]

Waiting validation with customers

[stonebuzz]

@Lainow

can you rebase, it is ok from customer ?