Use EnforcedStyle: consistent for FirstArrayElementIndentation

What does this MR do and why?

Implements the proposal in gitlab-org/ruby/gems/gitlab-styles#42 (closed) to use EnforcedStyle: consistent on Layout/FirstArrayElementIndentation and Layout/FirstHashElementIndentation.

Once the gitlab-styles project is updated, we can remove the configuration in .rubocop.yml.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #239356 and gitlab-org/ruby/gems/gitlab-styles#42 (closed)