Fix deprecation warning with dry-run option

What does this MR do?

This MR updates the way to call create secret with the dry-run option and removes the deprecation warning. There should be no change to the existing functionality.

$ create_secret
W1215 02:34:12.716629      25 helpers.go:553] --dry-run is deprecated and can be replaced with --dry-run=client.
secret "gitlab-registry-docker" deleted
secret/gitlab-registry-docker replaced

From the doc,

You can use the --dry-run=client flag to preview the object that would be sent to your cluster, without really submitting it.

Example job that demonstrate the deprecation warnings https://gitlab.com/gitlab-org/charts/gitlab/-/jobs/3472605397

Related issues

N/A

Checklist

See Definition of done.

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

Required

• Merge Request Title and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• When ready for review, MR is labeled "~workflow::ready for review" per the Distribution MR workflow

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for omnibus-gitlab opened
• Validate potential values for new configuration settings. Formats such as integer 10, duration 10s, URI scheme://user:passwd@host:port may require quotation or other special handling when rendered in a template and written to a configuration file.