Update FluxC to Latest Trunk Hash

[ParaskP7]

Relates To:

• WPAndroid: Update Fluxc and Login Libraries to Latest Trunk Version #17056
• WCAndroid: Update login library version #7240

This FluxC hash updates FluxC to that latest 'trunk' version where the RefreshSitesXMLRPCPayload data class becomes immutable.

As such, the refreshXmlRpcSites() method for the LoginUsernamePasswordFragment class needs updating to adhere to this change.

This step is required in order to avoid the client apps like WPAndroid and WCAndroid crashing while using a newer version of FluxC on their side due to transitive dependencies taking precedence and using the latest FluxC version, the one defined on the client's side.

[hafizrahman]

Accidentally restored the branch :)