`RSC18` not enforced by SDK

[AndyTWF]

RSC18 requires that trying to use basic authentication with TLS turned off should result in an error, enforced at the SDK level.

At the moment, we do not enforce this at the SDK level - which results in this not being enforced at all in the Realtime client but being enforced by the upstream service in the Rest client.

In theory, this is an unlikely situation to occur - the use of basic authentication is strongly discouraged, and usually reserved for testing purposes (e.g. in AAT we use a non-TLS proxy for fault testing).

┆Issue is synchronized with this Jira Task by Unito

[sync-by-unito[bot]]

➤ Automation for Jira commented:

The link to the corresponding Jira issue is https://ably.atlassian.net/browse/SDK-3423