Consider lowering the access rights required in Algolia_Send_Products::can_connect_to_algolia()

[w3bdesign]

At least we should be able to use a Write API Key if enough for our specific use case.

This requires to lower the access rights required in Algolia_Send_Products::can_connect_to_algolia()

Instead of using

self::$algolia->listApiKeys();

we could use

self::$algolia->listIndices();