Okta Dep Update

[kpcraig]

Description

This PR updates our Okta SDK dependency to v4, so that we transitively remove a go-jose dependency CVE-2024-28180. (Old versions of go-jose are pulled in other places as well and tracked in the issue named by the branch; this seems to be the only one that requires code changes on our part.)

Unfortunately, to get rid of the <=v2.6.2 vulerability, we had to move the okta-sdk to at least v3, which causes these breaking changes below. There didn't appear to be additional (relevant) changes between v3 and v4, so I moved to v4 directly.

This version is still broken (hence, draft); I put it here so I can link it in various sustaining channels/threads.

TODO only if you're a HashiCorp employee

• [ ] Backport Labels: If this PR is in the ENT repo and needs to be backported, backport
  to N, N-1, and N-2, using the backport/ent/x.x.x+ent labels. If this PR is in the CE repo, you should only backport to N, using the backport/x.x.x label, not the enterprise labels.
  • [ ] If this fixes a critical security vulnerability or severity 1 bug, it will also need to be backported to the current LTS versions of Vault. To ensure this, use all available enterprise labels.
• [X] Jira: If this change has an associated Jira, it's referenced either in the PR description, commit message, or branch name.