Fix unregisterForDataRoamingOff for eSIM when SIM is not ready.

Since registerForDataRoamingOff is not registered with addUnique,
thes are cases that is registered multiple times when eSIM is
repeatedly activated/deactivated.

Bug: 353631329
Test: atest FrameworksTelephonyTests:CarrierActionAgentTest
Flag: EXEMPT bugfix
Change-Id: Ief7d0c62f4c2d8afb7becfd89dd91c8c5ff8ad9e