fix: skip editor settings fetch when theme styles are disabled

[dcalhoun]

What?

Skip the /wp-block-editor/v1/settings fetch when shouldUseThemeStyles is disabled, regardless of the shouldUsePlugins flag.

Why?

Fix CMM-1921. Fix CMM-1163.

The guard in fetchEditorSettings() previously required both shouldUsePlugins and shouldUseThemeStyles to be false before skipping the fetch. This meant a site with plugins enabled but no support for the block editor settings endpoint would still attempt the fetch, resulting in a 404 error that could cause the editor to fail to load.

The editor settings endpoint is only relevant for theme styles — plugins have their own separate asset endpoint (/wpcom/v2/editor-assets).

How?

Changed the guard condition in fetchEditorSettings() from:

if !shouldUsePlugins && !shouldUseThemeStyles → skip

to:

if !shouldUseThemeStyles → skip

Applied to both iOS (RESTAPIRepository.swift) and Android (RESTAPIRepository.kt), with updated and additional test coverage on both platforms.

Testing Instructions

1. Configure a site that supports plugins (/wpcom/v2/editor-assets route exists) but does not support the block editor settings endpoint (/wp-block-editor/v1/settings route is absent).
2. Open the editor for that site.
3. Verify the editor loads without a 404 error for the settings endpoint.
4. Verify that a site with both plugins and theme styles enabled still fetches and applies editor settings correctly.

Accessibility Testing Instructions

N/A — no UI changes.

Screenshots or screencast

N/A — no UI changes.

[jkmassel]

With these changes, I was able to load the site that was erroring before the changes.