Add-On Config Area UX Improvements: Additional Manifest Section Visibility in Add-on Config area

[skanakal]

Setup

• Rancher version: 2.9.1
• Rancher UI Extensions:
• Browser type & version: any

Describe the bug

The Additional Manifest section in the RKE2 cluster configuration dashboard's "Add-On Config" area is frequently overlooked by users due to its location further down the page. Many customers fail to notice, resulting in missed configurations. Additionally, the form-based editor does not provide a clear or user-friendly way to interact with the additional manifest settings, confusing users accustomed to direct YAML editing.

To Reproduce

• create custom rke2 cluster with CNI: cilium
• Click on the Edit Config and click on "Add-on Config" under Cluster Configuration

Result
The additionalManifest section is hidden further down the "Add-On Config" area

Expected Result

The additionalManifest section should be more prominent and easily accessible, potentially through a collapsible or drop-down UI element that makes it clear or add another tab for additional manifest

Screenshots

maybe something like this:

Additional context

Internal ref: SURE-8962

[skanakal]

@gaktive @dkeightley Looks like this has been implemented here
#12066

I can confirm on 2.10 cluster:

[dkeightley]

Yes, thanks! I noticed it was also added in ~v2.9.4