settings: Fix JSON schema for `ExtensionCapabilityContent` (#39478)

This PR fixes the JSON schema for the `ExtensionCapabilityContent`.

Having the nested structs in the variants caused the `kind` property to
not be generated properly. Inlining the fields into the variants fixes
this.

Release Notes:

- N/A
504216cbbfMarshall Bowers committed on 10/3/2025, 4:58:47 PM· committed by GitHubparent3bf71c6
2 files changedLine totals unavailable