clientOptions configuration option is undocumented

[jamesmacwhite]

Description

The codebase allows for creating a Guzzle client with predefined client options per feed, but this is not documented in: https://docs.craftcms.com/feed-me/v4/get-started/configuration.html

Plugin::$plugin->service->createGuzzleClient($feedId);

When populating a valid feedId this would automatically provide any clientOptions values onto the Guzzle client.

Currently there is no mention of this anywhere in the documentation.