fetchMobileAppAttestationChallengeBlocking
Fetches a new "Challenge" from the Salesforce App Attestation External Client App (ECA) Plug-In.
This method is not intended for public use outside of Salesforce Mobile SDK.
Return
The Salesforce App Attestation ECA Plug-In challenge, or null if App Attestation is disabled (apiHostName is null) or the remote access consumer key is unavailable
Throws
if the network request fails
if the response cannot be parsed