Update GitLab exporter from 16.2 to 16.4

What does this MR do?

Update GitLab exporter from 16.2 to 16.4

Changelog: changed

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This MR is a spin off from !4601 (merged) which targets a newer gitlab exporter version that has no image yet. This MR targets 16.4 to unblock !4720 (merged).

Related issues

Author checklist

For general guidance, please follow our Contributing guide.

Required

For anything in this list which will not be completed, please provide a reason in the MR discussion.

• Merge Request Title and Description are up to date, accurate, and descriptive.
• MR targeting the appropriate branch.
• MR has a green pipeline.
• Documentation created/updated.
• Tests added/updated, and test plan for scenarios not covered by automated tests.
• Equivalent MR/issue for omnibus-gitlab opened.
  • Bump gitlab-exporter to 16.4.0 (gitlab-org/omnibus-gitlab!9025 - merged) • Robert Marshall • 18.10

Reviewers checklist

• MR has a green pipeline on https://gitlab.com/gitlab-org/charts/gitlab.
• Consider downstream impact to the Operator, as per evaluating impact from changes to GitLab chart.