Fix CtsRootBugreportTestCases on the following assumption

Assumption:
Since consent has already been denied, this call should
fail because consent cannot be requested twice for the
same bugreport.

The assumption comes from the CtsRootBugreportTestCases itself.

The bug was identified while diagnosing b/330056624

Failure,
expected: 6 (BUGREPORT_ERROR_NO_BUGREPORT_TO_RETRIEVE)
but was : 4 (BUGREPORT_ERROR_USER_CONSENT_TIMED_OUT)
        at
        ...testRetrieveBugreportConsentDenied(...)

Test: atest CtsRootBugreportTestCases

Bug: 330056624
Change-Id: I689d3558693c6766b5000cc1730620167db8827f