[backport v2.10.3] [BUG] Settings page does not handle errors anymore from Rancher version 2.10

[github-actions]

This is a backport issue for #13163, automatically created via GitHub Actions workflow initiated by @torchiaf

Original issue body:

SURE-9650

Rancher Server Setup

• Rancher version: 2.10.1
• Installation option (Docker install/Helm Chart):
  • Helm Chart on Kubernetes v1.28.2

User Information

• What is the role of the user logged in? (Admin/Cluster Owner/Cluster Member/Project Owner/Project Member/Custom)
  • If custom, define the set of permissions: Restricted Admin

Describe the bug
Hello,

We spotted that there is a regression in the error handling in Rancher dashboard settings page.
Indeed, we have a webhook preventing customers to modify some critical settings (not all).
In v2.9.7 when the webhook returned an error, the error was display in an error banner:

But in version 2.10.1, the error is never displayed. Only the save button becomes red:

To Reproduce

• Install a webhook in Rancher namespace preventing settings modifications
• Modify a setting

Result

Expected Result
The error message is displayed in a red banner in the top of the page

Screenshots
See in text

Additional context
It relates to issue #9183 but it's a bit different because in our case, it worked in previous Rancher minor version (2.9) while it never worked on the driver page side.

Thanks,
Best Regards,
Thomas