Merge branch 'tmillhouse/update-sentry-docs' into 'master'

Update Sentry DSN docs

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/173936



Merged-by: Lorena Ciutacu <lciutacu@gitlab.com>
Approved-by: Nick Klick <nicholas.klick@gmail.com>
Reviewed-by: Lorena Ciutacu <lciutacu@gitlab.com>
Co-authored-by: Taliesin Millhouse <tmillhouse@gitlab.com>