Support disableIfNoEncryptionCapabilities attribute in the
XML config specified by android:dataExtractionRules.The attribute, only applicable to <cloudBackup>, will disable cloud backup if the transport doesn't offer encryption.
Bug: 180523028
Test: atest FullbackupRulesHostSideTest
Change-Id: Ic6dab65834b51ff62c1e1a17b34b850f720681a1