Enable jest/prefer-to-have-length

What does this MR do and why?

Enables 'jest/prefer-to-have-length' to enforce our style guidelines.

Note: Depends on fixes at !196788 (merged)

References

Our docs recommend using toHaveLength where relevant at https://docs.gitlab.com/development/testing_guide/frontend_testing/#prefer-more-befitting-matchers. This enables the eslint rule in our project.

Screenshots or screen recordings

NA

How to set up and validate locally

A green pipeline is enough.

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #218360 (closed)