Connectors: Remove redundant helper and improve PHPDoc

Remove `_wp_connectors_get_connector_settings()` and inline `ksort()`
into `_wp_connectors_get_connector_script_module_data()`. Expand
`@return` and `@phpstan-return` array shapes for `wp_get_connector()`
and `wp_get_connectors()`. Make `logo_url` and `credentials_url` truly
optional. Rename test class to `wpGetConnectors`.

Developed in https://github.com/WordPress/wordpress-develop/pull/11227.

Follow-up to [61943].

Props gziolo, westonruter.
Fixes #64791.



git-svn-id: https://develop.svn.wordpress.org/trunk@61983 602fd350-edb4-49c9-b593-d223f7449a82