camera: Fix double ownership of AidlCameraDeviceCallbacks

Using std::make_shared with ndk::SharedRefBase objects causes memory
errors.

ndk::SharedRefBase::make uses std::static_pointer_cast internally, which
doesn't work when virtual inheritance is used. Virtual inheritance seems
unnecessary here, so I've removed it.

Bug: 226379467
Test: TH
Change-Id: I0df82ca30e3ebea4b48854f5a58796c22d169da5