docs: fix yq command for v4.32.2+

What does this MR do?

Update the yq command used in the docs for restoring GitLab secrets when restoring to a GitLab Helm Chart-deployed deployment.

Why:

$ yq -V
yq (https://github.com/mikefarah/yq/) version v4.33.2
$ yq -P . t.json
10:21:56 initCommand [WARN] JSON file output is now JSON by default (instead of yaml). Use '-oy' or '--output-format=yaml' for yaml output

Related issues

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.