Remove aggressive handover developer setting

The developer setting for aggressive wifi to mobile data handover is no
longer used by the framework, so it should not appear in the settings UI.

Bug: 72063774
Test: m RunSettingsRoboTests -j40
Test: Manually check developer options, make sure aggressive handover is gone
Change-Id: Id54c714fc82fb27abc0b4116f2b82be68cc6d151