Update subgroup delete rake task for ruby 3

What does this MR do and why?

Fixes the delete_permanently method of the delete_subgroups rake task to work with Ruby 3.

It's been failing here: https://ops.gitlab.net/gitlab-org/quality/staging/-/jobs/9009326

rake aborted!
ArgumentError: wrong number of arguments (given 2, expected 1)
/home/gitlab/qa/qa/tools/delete_subgroups.rb:74:in `subgroup_request'
/home/gitlab/qa/qa/tools/delete_subgroups.rb:130:in `block in delete_permanently'
/home/gitlab/qa/qa/tools/delete_subgroups.rb:124:in `each'
/home/gitlab/qa/qa/tools/delete_subgroups.rb:124:in `delete_permanently'
/home/gitlab/qa/qa/tools/delete_subgroups.rb:39:in `run'
/home/gitlab/qa/Rakefile:9:in `block in <top (required)>'
/usr/local/bin/bundle:23:in `load'
/usr/local/bin/bundle:23:in `<main>'
Tasks: TOP => delete_subgroups
(See full trace by running task with --trace)

We just need to prefix the argument with a double splat now.

Tested locally in GDK with Ruby 3.

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