Documentation: Clarify how to provide Temporary Credentials when using a Custom Credentials Provider

[ruisebas]

On which framework/platform would you like to see this feature implemented?

iOS

Which UI component is this feature-request for?

Liveness

Please describe your feature-request in detail.

The Custom Credentials Provider section under the Liveness startup guide has a simple code snippet on how to provide credentials:

struct MyCredentialsProvider: AWSCredentialsProvider {
    func fetchAWSCredentials() async throws -> AWSCredentials { 
        // Fetch the credentials
    }
}

However, if temporary credentials are provided, developers must return an instance of a type conforming to AWSTemporaryCredentials instead, otherwise the service will reject them.

Please describe a solution you'd like.

Just have a callout in this section stating that AWSTemporaryCredentials exists and when it should be used.

We love contributors! Is this something you'd be interested in working on?

• 👋 I may be able to implement this feature request.
• ⚠️ This feature might incur a breaking change.

[github-actions]

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[thaddmt]

Transferring this task to the swift library as it seems specific to the Swift liveness component