fix: handle symbols in constraintToString method with array

[adrienboulle]

Description

When implementing custom validators and using array of symbols as constraints, an error is raised when the error message is generated for a failed validation.

Checklist

• the pull request title describes what this PR does (not a vague title like Update index.md)
• the pull request targets the default branch of the repository (develop)
• the code follows the established code style of the repository
  • npm run prettier:check passes
  • npm run lint:check passes
• tests are added for the changes I made (if any source code was modified)
• documentation added or updated
• I have run the project locally and verified that there are no errors

Fixes

fixes #2026

[adrienboulle]

@NoNameProvided would you mind having a look at this PR?

[adrienboulle]

@braaar would you mind having a look at this PR?

[adrienboulle]

hi @braaar I'm having trouble having this PR reviews, let me know if I'm doing anything wrong I would be more than happy to fix it :)

thx a lot!

[adrienboulle]

hi @braaar could you review this quick PR ?
It's just a following PR regarding this one: #1794