fix: Upgrading gitlab-labkit to properly format time for User Experience SLIs on JSON logs

What does this MR do and why?

The change here upgrades gitlab-labkit to v1.1.3, that fixes a bug where User Experience SLIs logs weren't correctly formatting time values using the RFC3339.

This new version also validates the User Experience SLIs against valid feature categories.

References

Part of https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/incident-management/-/issues/2448.

Screenshots or screen recordings

Before	After

How to set up and validate locally

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.