[CDCA] Set real caller for work lock activity

BiometricPrompt internally relies on caller's package name for defaut
logo information. ConfirmDeviceCredentialActivity then needs to set
the real caller to getCallingActivity().

However, when WorkLockActivity uses CDCA, the real caller should not be
itself, instead, it should be EXTRA_PACKAGE_NAME. This CL passes
this extra to CDCA.

Test: manual test with work account
Flag: EXEMPT bug fix
Bug: 378036094

Change-Id: I417857d307dac136372150d39dde8519ca7c17f4