[EKS] [BUG]: certificate signing requests are not issued if the request object starts with `csr-`

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**Tell us about your request**

Context: https://docs.aws.amazon.com/eks/latest/userguide/cert-signing.html

When a `CertificateSigningRequest` object is created with a name including the prefix `csr-`, the EKS control plane silently discards it and doesn't sign the request.

**edit:** by "discard" I mean that its status remains `Approved` forever, instead of `Approved,Issued`.

**Which service(s) is this request for?**

EKS

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**

I believe this should be either fixed or documented, because:

1. It's very obscure.
1. Prefixing the name of a CSR with "csr-" feels natural enough that a lot of people might run into this issue, and potentially waste a lot of time troubleshooting it.

**Are you currently working around this issue?**

Yes, by generating certificate signing requests with names that do not start with `csr-`.

**Additional context**

\-

**Attachments**

\-

Start with the EKS certificate-signing documentation linked in the issue and reproduce the behavior using a CertificateSigningRequest whose name starts with `csr-`. Confirm the status remains `Approved` rather than `Approved,Issued`, then determine whether the intended outcome is a service fix or a documentation change; the issue mentions no repository files or tests.

Written by the indexing model from the issue text.