[backport v2.14] [BUG] Project Scoped Secrets not editable after upgrading to 2.12.x

[rancher-ui-project-bot]

This is a backport issue for #15547, automatically created via GitHub Actions workflow initiated by @richard-cox

Original issue body:

SURE-10810

Rancher Server Setup

• Rancher version: 2.12.2
• Installation option (Docker install/Helm Chart): Helm Chart on RKE2
• Proxy/Cert Details:

Information about the Cluster

• Kubernetes version: 1.33.4 (local), 1.32.5 (downstream)
• Cluster Type (Local/Downstream): Both
  • If downstream, what type of cluster? (Custom/Imported or specify provider for Hosted/Infrastructure Provider): Custom (RKE2)

User Information

• What is the role of the user logged in? Admin

Describe the bug
After upgrading from 2.11.x to 2.12.x, we can't edit/delete Project Scoped Secret in the UI.
On the new "Storage - Project Secrets" page there is only the phrase "There are no rows to show." while they still exist on the cluster.
Even if you create a new Project Scoped Secret it doesn't appear there.
We have to edit the old Project Scoped Secret (TLS) to renew it, but we can't do anything.
I think this is happening because the project created on Rancher 2.9 were named differently.
On the local rancher cluster, if I check the namespaces I can see two types of projects:

1. The newer one, with a nomenclature like: <cluster-id>-<project-id>
2. The older one, with a nomenclature like: <project-id>

Maybe the new UI can't see the older one?

To Reproduce

1. Install a Rancher 2.9 from scratch;
2. Enable legacy features, and add a Project Scoped secret
3. Upgrade that Rancher to 2.10, then to 2.11, then to 2.12

Result
Now you can't see any Project Scoped Secret.

Expected Result
Project Scoped Secrets should be there.

Screenshots

[gaktive]

Pushing version since forward port still blocked.