Avoid forever loading / failure page when creating resource by YAML and schemaDefinition fetch fails

[richard-cox]

Setup

• Rancher version: 2.9.0

Describe the bug

• schemeDefinition is required to populate suggested properties when creating a resource via the YAML editor
• sometimes this fails and the UX isn't great

To Reproduce

• need to hardcode the failure, or find resource that does not contain a definition (TBD)

Result

• forever loading indicator

Expected Result

• empty yaml editor, console warning